fix: use debian:trixie-slim runtime to match builder glibc 2.38

rust:1.95-slim is trixie-based (glibc 2.38); bookworm-slim only has 2.36, causing a crash on startup.
fix: ignore RUSTSEC-2023-0071 in release workflow cargo audit
2026-05-05 03:36:22 +02:00 · 2026-05-05 03:16:50 +02:00 · 2026-05-05 03:12:23 +02:00 · 2026-05-05 02:48:40 +02:00 · 2026-05-05 02:39:03 +02:00 · 2026-05-05 02:24:29 +02:00
36 changed files with 4605 additions and 602 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -19,7 +19,6 @@ build/

 # Rust
 target/
-Cargo.lock
 debug/
 release/

@@ -43,3 +42,4 @@ conductor/
 docs/review.md
 docs/tutortool_audit.md
 *.log
+screenshot-*.png
--- a/5
+++ b/5
@@ -5,11 +5,12 @@ RUN corepack enable && corepack prepare pnpm --activate
 COPY frontend/package.json frontend/pnpm-lock.yaml ./
 RUN pnpm install --frozen-lockfile
 COPY frontend/ ./
+RUN pnpm svelte-kit sync
 RUN pnpm run check
 RUN pnpm run build

 # --- Backend Build ---
-FROM rust:1.95-slim AS backend-builder
+FROM rust:1.95-slim-bookworm AS backend-builder
 WORKDIR /app/backend
 COPY backend/Cargo.toml backend/Cargo.lock ./
 RUN mkdir src && echo "fn main() {}" > src/main.rs && cargo build --release && rm -rf src
@@ -19,7 +20,7 @@ COPY backend/demo ./demo
 RUN touch src/main.rs && cargo build --release

 # --- Runtime ---
-FROM debian:bookworm-slim
+FROM debian:trixie-slim
 RUN apt-get update && apt-get install -y ca-certificates curl && rm -rf /var/lib/apt/lists/*
 RUN useradd -u 1000 -m app
 WORKDIR /app
--- a/11
+++ b/11
@@ -1,3 +1,5 @@
+SHELL := /bin/bash
+
 .PHONY: dev dev-backend dev-frontend build test compose-up seed-demo \
        test-up test-down test-reset test-rebuild test-e2e

@@ -58,10 +60,19 @@ test-up:
 		exit 0; \
 	fi; \
 	[ -f "$$TT_TEST_DB" ] || $(MAKE) test-rebuild; \
+	rm -f data/test/.port; \
 	DATABASE_URL="sqlite:$$TT_TEST_DB" PORT=$$TT_TEST_PORT TT_TEST_MODE=1 JWT_SECRET=testsecret STATIC_DIR=frontend/build \
 		cargo run --manifest-path backend/Cargo.toml &>/tmp/tutortool-test.log & \
 	echo $$! > data/test/.pid; \
 	echo "[test-up] Backend PID $$(cat data/test/.pid) starting on port $$TT_TEST_PORT..."; \
+	if [ "$$TT_TEST_PORT" = "0" ]; then \
+		for i in $$(seq 1 30); do \
+			[ -f data/test/.port ] && break; \
+			sleep 1; \
+		done; \
+		. scripts/test-env.sh; \
+		echo "[test-up] Backend bound to port $$TT_TEST_PORT"; \
+	fi; \
 	for i in $$(seq 1 30); do \
 		curl -fs "$$TT_BASE_URL/health" >/dev/null 2>&1 && break; \
 		sleep 1; \
--- a/backend/Cargo.lock
+++ b/backend/Cargo.lock
--- a/backend/Cargo.toml
+++ b/backend/Cargo.toml
@@ -11,7 +11,7 @@ tokio = { version = "1", features = ["full"] }
 sqlx = { version = "0.8", features = ["sqlite", "runtime-tokio", "macros", "migrate"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
-jsonwebtoken = { version = "10", features = ["rust_crypto"] }
+jsonwebtoken = { version = "10", features = ["aws_lc_rs"] }
 bcrypt = "0.19"
 argon2 = "0.5"
 tower-http = { version = "0.6", features = ["fs", "cors", "trace", "set-header"] }
--- a/backend/demo/demo_seed.sql
+++ b/backend/demo/demo_seed.sql
@@ -14,30 +14,222 @@ VALUES (1, 1);
 -- Rooms
 INSERT OR IGNORE INTO rooms (id, name, layout_json)
 VALUES (1, 'Room A (Small)', '[
-    { "id": "T1", "label": "T1", "x": 90, "y": 150, "width": 200, "height": 70, "type": "table" },
-    { "id": "T2", "label": "T2", "x": 470, "y": 150, "width": 200, "height": 70, "type": "table" },
-    { "id": "T3", "label": "T3", "x": 90, "y": 320, "width": 200, "height": 70, "type": "table" },
-    { "id": "T4", "label": "T4", "x": 470, "y": 320, "width": 200, "height": 70, "type": "table" },
-    { "id": "T1-1", "label": "1", "x": 146.0, "y": 128, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T1-2", "label": "2", "x": 234.0, "y": 128, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T1-3", "label": "3", "x": 146.0, "y": 242, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T1-4", "label": "4", "x": 234.0, "y": 242, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T1-5", "label": "5", "x": 316, "y": 185.0, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T2-1", "label": "1", "x": 526.0, "y": 128, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T2-2", "label": "2", "x": 614.0, "y": 128, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T2-3", "label": "3", "x": 526.0, "y": 242, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T2-4", "label": "4", "x": 614.0, "y": 242, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T2-5", "label": "5", "x": 696, "y": 185.0, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T3-1", "label": "1", "x": 146.0, "y": 298, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T3-2", "label": "2", "x": 234.0, "y": 298, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T3-3", "label": "3", "x": 146.0, "y": 412, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T3-4", "label": "4", "x": 234.0, "y": 412, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T3-5", "label": "5", "x": 316, "y": 355.0, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T4-1", "label": "1", "x": 526.0, "y": 298, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T4-2", "label": "2", "x": 614.0, "y": 298, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T4-3", "label": "3", "x": 526.0, "y": 412, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T4-4", "label": "4", "x": 614.0, "y": 412, "width": 36, "height": 36, "type": "seat" },
-    { "id": "T4-5", "label": "5", "x": 696, "y": 355.0, "width": 36, "height": 36, "type": "seat" }
+    {
+        "id": "T1",
+        "label": "T1",
+        "x": 2.25,
+        "y": 3.75,
+        "width": 5.0,
+        "height": 1.75,
+        "type": "table"
+    },
+    {
+        "id": "T2",
+        "label": "T2",
+        "x": 11.75,
+        "y": 3.75,
+        "width": 5.0,
+        "height": 1.75,
+        "type": "table"
+    },
+    {
+        "id": "T3",
+        "label": "T3",
+        "x": 2.25,
+        "y": 8.0,
+        "width": 5.0,
+        "height": 1.75,
+        "type": "table"
+    },
+    {
+        "id": "T4",
+        "label": "T4",
+        "x": 11.75,
+        "y": 8.0,
+        "width": 5.0,
+        "height": 1.75,
+        "type": "table"
+    },
+    {
+        "id": "T1-1",
+        "label": "1",
+        "x": 3.65,
+        "y": 3.2,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T1-2",
+        "label": "2",
+        "x": 5.85,
+        "y": 3.2,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T1-3",
+        "label": "3",
+        "x": 3.65,
+        "y": 6.05,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T1-4",
+        "label": "4",
+        "x": 5.85,
+        "y": 6.05,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T1-5",
+        "label": "5",
+        "x": 7.9,
+        "y": 4.62,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T2-1",
+        "label": "1",
+        "x": 13.15,
+        "y": 3.2,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T2-2",
+        "label": "2",
+        "x": 15.35,
+        "y": 3.2,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T2-3",
+        "label": "3",
+        "x": 13.15,
+        "y": 6.05,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T2-4",
+        "label": "4",
+        "x": 15.35,
+        "y": 6.05,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T2-5",
+        "label": "5",
+        "x": 17.4,
+        "y": 4.62,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T3-1",
+        "label": "1",
+        "x": 3.65,
+        "y": 7.45,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T3-2",
+        "label": "2",
+        "x": 5.85,
+        "y": 7.45,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T3-3",
+        "label": "3",
+        "x": 3.65,
+        "y": 10.3,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T3-4",
+        "label": "4",
+        "x": 5.85,
+        "y": 10.3,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T3-5",
+        "label": "5",
+        "x": 7.9,
+        "y": 8.88,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T4-1",
+        "label": "1",
+        "x": 13.15,
+        "y": 7.45,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T4-2",
+        "label": "2",
+        "x": 15.35,
+        "y": 7.45,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T4-3",
+        "label": "3",
+        "x": 13.15,
+        "y": 10.3,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T4-4",
+        "label": "4",
+        "x": 15.35,
+        "y": 10.3,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    },
+    {
+        "id": "T4-5",
+        "label": "5",
+        "x": 17.4,
+        "y": 8.88,
+        "width": 0.9,
+        "height": 0.9,
+        "type": "seat"
+    }
 ]');

 -- Students
--- a/backend/migrations/003_normalize_room_layout_units.sql
+++ b/backend/migrations/003_normalize_room_layout_units.sql
@@ -0,0 +1,26 @@
+-- Normalize room layout units: divide pixel-scale coordinates by 40.
+-- Only runs on rooms that contain at least one element with a coordinate > 50
+-- (i.e. still in pixel scale). Once identified, all elements are converted
+-- unconditionally — no per-element heuristic needed.
+UPDATE rooms
+SET layout_json = (
+    SELECT json_group_array(
+        json_object(
+            'id', json_extract(value, '$.id'),
+            'label', json_extract(value, '$.label'),
+            'x', ROUND(CAST(json_extract(value, '$.x') AS REAL) / 40.0, 2),
+            'y', ROUND(CAST(json_extract(value, '$.y') AS REAL) / 40.0, 2),
+            'width', ROUND(CAST(json_extract(value, '$.width') AS REAL) / 40.0, 2),
+            'height', ROUND(CAST(json_extract(value, '$.height') AS REAL) / 40.0, 2),
+            'type', json_extract(value, '$.type')
+        )
+    )
+    FROM json_each(rooms.layout_json)
+)
+WHERE EXISTS (
+    SELECT 1 FROM json_each(rooms.layout_json)
+    WHERE json_extract(value, '$.x') > 50
+       OR json_extract(value, '$.y') > 50
+       OR json_extract(value, '$.width') > 50
+       OR json_extract(value, '$.height') > 50
+);
--- a/backend/migrations/004_tutor_is_active.sql
+++ b/backend/migrations/004_tutor_is_active.sql
@@ -0,0 +1 @@
+ALTER TABLE tutors ADD COLUMN is_active BOOLEAN NOT NULL DEFAULT 1;
--- a/backend/src/main.rs
+++ b/backend/src/main.rs
@@ -85,7 +85,14 @@ async fn main() {
    let listener = tokio::net::TcpListener::bind(&addr)
        .await
        .expect("failed to bind");
-    tracing::info!("listening on {}", addr);
+    let actual_addr = listener.local_addr().expect("failed to get local addr");
+    tracing::info!("listening on {}", actual_addr);
+
+    // When started with PORT=0 (random), write actual port so the test harness can discover it
+    if port == "0" {
+        let _ = std::fs::create_dir_all("data/test");
+        let _ = std::fs::write("data/test/.port", actual_addr.port().to_string());
+    }

    axum::serve(
        listener,
--- a/backend/src/models.rs
+++ b/backend/src/models.rs
@@ -14,6 +14,7 @@ pub struct Tutor {
    pub name: String,
    pub email: String,
    pub is_superadmin: bool,
+    pub is_active: bool,
 }

 #[derive(Debug, Clone, Serialize, sqlx::FromRow)]
@@ -48,6 +49,8 @@ pub struct Slot {
    pub end_time: String,
    pub status: String,
    pub code: Option<String>,
+    #[sqlx(skip)]
+    pub layout: Option<Vec<LayoutElement>>,
 }

 #[derive(Debug, Clone, Serialize, sqlx::FromRow)]
@@ -131,6 +134,10 @@ pub struct AssignTutor {
    pub tutor_id: i64,
 }
 #[derive(Deserialize)]
+pub struct SetTutorActive {
+    pub is_active: bool,
+}
+#[derive(Deserialize)]
 pub struct CheckinRequest {
    pub code: String,
    pub student_id: i64,
--- a/backend/src/routes/attendance.rs
+++ b/backend/src/routes/attendance.rs
@@ -79,14 +79,52 @@ async fn get_session_attendance(
    .fetch_all(&pool)
    .await?;

-    // Get all slots for the session
-    let slots: Vec<crate::models::Slot> = sqlx::query_as(
-        "SELECT id, session_id, room_id, tutor_id, start_time, end_time, status, code FROM slots WHERE session_id = ?"
+    type SlotRow = (
+        i64,
+        i64,
+        Option<i64>,
+        i64,
+        String,
+        String,
+        String,
+        Option<String>,
+        Option<String>,
+    );
+    let slot_rows: Vec<SlotRow> = sqlx::query_as(
+        "SELECT s.id, s.session_id, s.room_id, s.tutor_id, s.start_time, s.end_time, s.status, s.code, r.layout_json
+         FROM slots s
+         LEFT JOIN rooms r ON s.room_id = r.id
+         WHERE s.session_id = ?"
    )
    .bind(session_id)
    .fetch_all(&pool)
    .await?;

+    let mut slots = Vec::new();
+    for row in slot_rows {
+        let layout: Option<Vec<crate::models::LayoutElement>> = match row.8 {
+            Some(ref json_str) => match serde_json::from_str(json_str) {
+                Ok(v) => Some(v),
+                Err(e) => {
+                    tracing::error!(slot_id = row.0, err = %e, "failed to deserialize room layout_json");
+                    None
+                }
+            },
+            None => None,
+        };
+        slots.push(crate::models::Slot {
+            id: row.0,
+            session_id: row.1,
+            room_id: row.2,
+            tutor_id: row.3,
+            start_time: row.4,
+            end_time: row.5,
+            status: row.6,
+            code: row.7,
+            layout,
+        });
+    }
+
    // Get all attendances for these slots
    let attendances: Vec<crate::models::Attendance> = sqlx::query_as(
        "SELECT id, slot_id, student_id, seat_id, checked_in_at FROM attendances WHERE slot_id IN (SELECT id FROM slots WHERE session_id = ?)"
--- a/backend/src/routes/auth_routes.rs
+++ b/backend/src/routes/auth_routes.rs
@@ -24,14 +24,14 @@ async fn login(
    jar: CookieJar,
    Json(req): Json<LoginRequest>,
 ) -> Result<(CookieJar, Json<Value>), AppError> {
-    let tutor: Option<(i64, String, String, bool)> = sqlx::query_as(
-        "SELECT id, email, password_hash, is_superadmin FROM tutors WHERE email = ?",
+    let tutor: Option<(i64, String, String, bool, bool)> = sqlx::query_as(
+        "SELECT id, email, password_hash, is_superadmin, is_active FROM tutors WHERE email = ?",
    )
    .bind(&req.email)
    .fetch_optional(&state.pool)
    .await?;

-    let (id, _email, hash, is_superadmin) = tutor.ok_or(AppError::Unauthorized)?;
+    let (id, _email, hash, is_superadmin, is_active) = tutor.ok_or(AppError::Unauthorized)?;

    let mut rehash_needed = false;
    let mut authed = false;
@@ -57,6 +57,11 @@ async fn login(
        return Err(AppError::Unauthorized);
    }

+    // Reject inactive tutors AFTER password verification to avoid timing attacks or info leakage
+    if !is_active {
+        return Err(AppError::Unauthorized);
+    }
+
    // Lazy rehash to Argon2 if we used bcrypt
    if rehash_needed {
        let salt = SaltString::generate(&mut rand::thread_rng());
@@ -106,6 +111,15 @@ async fn refresh(

    let claims = auth::decode_jwt(&refresh_token, &state.jwt_secret, true)?;

+    // Re-check is_active so deactivated tutors cannot refresh their session
+    let is_active: Option<bool> = sqlx::query_scalar("SELECT is_active FROM tutors WHERE id = ?")
+        .bind(claims.sub)
+        .fetch_optional(&state.pool)
+        .await?;
+    if !is_active.unwrap_or(false) {
+        return Err(AppError::Unauthorized);
+    }
+
    // Issue new access token
    let access_token =
        auth::encode_jwt(claims.sub, claims.is_superadmin, &state.jwt_secret, false)?;
@@ -172,10 +186,11 @@ mod tests {
    #[sqlx::test(migrations = "./migrations")]
    async fn login_returns_superadmin_and_cookies(pool: sqlx::SqlitePool) {
        let hash = bcrypt::hash("secret", 4).unwrap();
-        sqlx::query("INSERT INTO tutors (name,email,password_hash) VALUES (?,?,?)")
+        sqlx::query("INSERT INTO tutors (name,email,password_hash,is_active) VALUES (?,?,?,?)")
            .bind("Test")
            .bind("t@test.com")
            .bind(&hash)
+            .bind(true)
            .execute(&pool)
            .await
            .unwrap();
--- a/backend/src/routes/courses.rs
+++ b/backend/src/routes/courses.rs
@@ -65,6 +65,20 @@ async fn assign_tutor(
    if !claims.is_superadmin {
        return Err(AppError::Unauthorized);
    }
+
+    // Verify tutor exists and is active
+    let maybe_active: Option<bool> =
+        sqlx::query_scalar("SELECT is_active FROM tutors WHERE id = ?")
+            .bind(req.tutor_id)
+            .fetch_optional(&pool)
+            .await?;
+    let is_active = maybe_active.ok_or(AppError::NotFound)?;
+    if !is_active {
+        return Err(AppError::BadRequest(
+            "Tutor:in ist inaktiv und kann nicht zugewiesen werden.".into(),
+        ));
+    }
+
    sqlx::query("INSERT OR IGNORE INTO tutor_courses (tutor_id, course_id) VALUES (?, ?)")
        .bind(req.tutor_id)
        .bind(course_id)
@@ -101,7 +115,7 @@ async fn list_assigned_tutors(
    }

    let tutors = sqlx::query_as::<_, crate::models::Tutor>(
-        "SELECT t.id, t.name, t.email, t.is_superadmin FROM tutors t
+        "SELECT t.id, t.name, t.email, t.is_superadmin, t.is_active FROM tutors t
         JOIN tutor_courses tc ON tc.tutor_id = t.id
         WHERE tc.course_id = ?",
    )
--- a/backend/src/routes/rooms.rs
+++ b/backend/src/routes/rooms.rs
@@ -51,6 +51,23 @@ fn validate_layout(layout: &[LayoutElement]) -> Result<(), AppError> {
                "x, y, width, height must all be >= 0.0".into(),
            ));
        }
+        // MAX_CANVAS = 100 bound
+        if elem.x + elem.width > 100.0 || elem.y + elem.height > 100.0 {
+            return Err(AppError::BadRequest(
+                "element outside of 100x100 canvas".into(),
+            ));
+        }
+        // 0.5-step multiple check — use epsilon comparison to avoid IEEE-754 fract() edge cases
+        let not_half_step = |v: f64| ((v * 2.0).round() - v * 2.0).abs() > f64::EPSILON;
+        if not_half_step(elem.x)
+            || not_half_step(elem.y)
+            || not_half_step(elem.width)
+            || not_half_step(elem.height)
+        {
+            return Err(AppError::BadRequest(
+                "coords/dims must be multiples of 0.5".into(),
+            ));
+        }
        // seat labels must be unique among seats
        if elem.kind == "seat" {
            if elem.label.is_empty() {
@@ -143,10 +160,39 @@ async fn update_room_layout(
    Ok(Json(json!({"id": id})))
 }

+async fn delete_room(
+    _claims: TutorClaims,
+    State(pool): State<SqlitePool>,
+    Path(id): Path<i64>,
+) -> Result<StatusCode, AppError> {
+    // Check if room is attached to any slots
+    let slot_count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM slots WHERE room_id = ?")
+        .bind(id)
+        .fetch_one(&pool)
+        .await?;
+    if slot_count > 0 {
+        return Err(AppError::Conflict(format!(
+            "Raum hat noch {} Slot(s). Bitte zuerst entfernen.",
+            slot_count
+        )));
+    }
+
+    let result = sqlx::query("DELETE FROM rooms WHERE id = ?")
+        .bind(id)
+        .execute(&pool)
+        .await?;
+
+    if result.rows_affected() == 0 {
+        return Err(AppError::NotFound);
+    }
+
+    Ok(StatusCode::NO_CONTENT)
+}
+
 pub fn router() -> Router<AppState> {
    Router::new()
        .route("/api/admin/rooms", get(list_rooms).post(create_room))
-        .route("/api/admin/rooms/{id}", get(get_room))
+        .route("/api/admin/rooms/{id}", get(get_room).delete(delete_room))
        .route("/api/admin/rooms/{id}/layout", put(update_room_layout))
 }

@@ -321,6 +367,89 @@ mod tests {
        assert_eq!(status, StatusCode::BAD_REQUEST);
    }

+    #[sqlx::test(migrations = "./migrations")]
+    async fn layout_validation_rejects_out_of_bounds(pool: sqlx::SqlitePool) {
+        let (app, auth) = build_test_app(pool).await;
+        let layout = json!([
+            {"id":"s1","label":"A1","x":99.0,"y":0.0,"width":2.0,"height":1.0,"type":"seat"}
+        ]);
+        let (status, _) = post_json(
+            app,
+            "/api/admin/rooms",
+            &auth,
+            json!({"name":"Bad","layout":layout}),
+        )
+        .await;
+        assert_eq!(status, StatusCode::BAD_REQUEST);
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn layout_validation_rejects_non_step(pool: sqlx::SqlitePool) {
+        let (app, auth) = build_test_app(pool).await;
+        let layout = json!([
+            {"id":"s1","label":"A1","x":0.1,"y":0.0,"width":1.0,"height":1.0,"type":"seat"}
+        ]);
+        let (status, _) = post_json(
+            app,
+            "/api/admin/rooms",
+            &auth,
+            json!({"name":"Bad","layout":layout}),
+        )
+        .await;
+        assert_eq!(status, StatusCode::BAD_REQUEST);
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn delete_room_with_no_slots_succeeds(pool: sqlx::SqlitePool) {
+        use crate::test_helpers::delete;
+        let (app, auth) = build_test_app(pool.clone()).await;
+        // create room
+        let (_, body) = post_json(
+            app.clone(),
+            "/api/admin/rooms",
+            &auth,
+            json!({"name":"R1","layout":[{"id":"s1","label":"A1","x":0.0,"y":0.0,"width":1.0,"height":1.0,"type":"seat"}]}),
+        )
+        .await;
+        let id = serde_json::from_slice::<Value>(&body).unwrap()["id"]
+            .as_i64()
+            .unwrap();
+
+        let (status, _) = delete(app, &format!("/api/admin/rooms/{id}"), &auth).await;
+        assert_eq!(status, StatusCode::NO_CONTENT);
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn delete_room_with_slot_returns_409(pool: sqlx::SqlitePool) {
+        use crate::test_helpers::delete;
+        let (app, auth) = build_test_app(pool.clone()).await;
+        // create room
+        let (_, body) = post_json(
+            app.clone(),
+            "/api/admin/rooms",
+            &auth,
+            json!({"name":"R1","layout":[{"id":"s1","label":"A1","x":0.0,"y":0.0,"width":1.0,"height":1.0,"type":"seat"}]}),
+        )
+        .await;
+        let room_id = serde_json::from_slice::<Value>(&body).unwrap()["id"]
+            .as_i64()
+            .unwrap();
+
+        let course_id: i64 = sqlx::query_scalar(
+            "INSERT INTO courses (name, semester) VALUES ('FP', 'SS2026') RETURNING id",
+        )
+        .fetch_one(&pool)
+        .await
+        .unwrap();
+        let session_id: i64 = sqlx::query_scalar("INSERT INTO sessions (course_id, week_nr, date) VALUES (?, 1, '2026-05-04') RETURNING id").bind(course_id).fetch_one(&pool).await.unwrap();
+        sqlx::query("INSERT INTO slots (session_id, room_id, tutor_id, start_time, end_time, status) VALUES (?, ?, 1, '09:00', '10:00', 'open')")
+            .bind(session_id).bind(room_id).execute(&pool).await.unwrap();
+
+        let (status, body) = delete(app, &format!("/api/admin/rooms/{room_id}"), &auth).await;
+        assert_eq!(status, StatusCode::CONFLICT);
+        assert!(String::from_utf8_lossy(&body).contains("Slot"));
+    }
+
    #[sqlx::test(migrations = "./migrations")]
    async fn get_room_not_found(pool: sqlx::SqlitePool) {
        let (app, auth) = build_test_app(pool).await;
--- a/backend/src/routes/sessions.rs
+++ b/backend/src/routes/sessions.rs
@@ -108,16 +108,19 @@ async fn create_slot(
    // Verify requesting tutor has access to the course
    super::verify_tutor_course_access(&pool, claims.sub, course_id).await?;

-    // Verify the slot's tutor_id belongs to this course
-    let member: Option<(i64,)> =
-        sqlx::query_as("SELECT 1 FROM tutor_courses WHERE tutor_id = ? AND course_id = ?")
-            .bind(req.tutor_id)
-            .bind(course_id)
-            .fetch_optional(&pool)
-            .await?;
+    // Verify the slot's tutor_id belongs to this course AND is active
+    let member: Option<(i64,)> = sqlx::query_as(
+        "SELECT 1 FROM tutor_courses tc
+                        JOIN tutors t ON t.id = tc.tutor_id
+                        WHERE tc.tutor_id = ? AND tc.course_id = ? AND t.is_active = 1",
+    )
+    .bind(req.tutor_id)
+    .bind(course_id)
+    .fetch_optional(&pool)
+    .await?;
    if member.is_none() {
        return Err(AppError::BadRequest(
-            "tutor_id is not a member of this course".into(),
+            "Tutor:in ist in diesem Kurs nicht aktiv oder existiert nicht.".into(),
        ));
    }

--- a/backend/src/routes/tutors.rs
+++ b/backend/src/routes/tutors.rs
@@ -2,13 +2,13 @@ use crate::{
    AppState,
    auth::TutorClaims,
    error::AppError,
-    models::{CreateTutor, Tutor},
+    models::{CreateTutor, SetTutorActive, Tutor},
 };
 use axum::{
    Json, Router,
    extract::{Path, State},
    http::StatusCode,
-    routing::{delete, get},
+    routing::{delete, get, patch},
 };
 use sqlx::SqlitePool;

@@ -21,7 +21,7 @@ async fn list_tutors(
    }

    let tutors = sqlx::query_as::<_, Tutor>(
-        "SELECT id, name, email, is_superadmin FROM tutors ORDER BY name",
+        "SELECT id, name, email, is_superadmin, is_active FROM tutors ORDER BY name",
    )
    .fetch_all(&pool)
    .await?;
@@ -50,7 +50,7 @@ async fn create_tutor(
        .to_string();

    let id = sqlx::query(
-        "INSERT INTO tutors (name, email, password_hash, is_superadmin) VALUES (?, ?, ?, ?)",
+        "INSERT INTO tutors (name, email, password_hash, is_superadmin, is_active) VALUES (?, ?, ?, ?, 1)",
    )
    .bind(&req.name)
    .bind(&req.email)
@@ -67,10 +67,39 @@ async fn create_tutor(
            name: req.name,
            email: req.email,
            is_superadmin: req.is_superadmin,
+            is_active: true,
        }),
    ))
 }

+async fn set_tutor_active(
+    claims: TutorClaims,
+    State(pool): State<SqlitePool>,
+    Path(id): Path<i64>,
+    Json(req): Json<SetTutorActive>,
+) -> Result<StatusCode, AppError> {
+    if !claims.is_superadmin {
+        return Err(AppError::Unauthorized);
+    }
+
+    // Don't allow deactivating yourself
+    if claims.sub == id && !req.is_active {
+        return Err(AppError::Conflict("cannot deactivate yourself".into()));
+    }
+
+    let result = sqlx::query("UPDATE tutors SET is_active = ? WHERE id = ?")
+        .bind(req.is_active)
+        .bind(id)
+        .execute(&pool)
+        .await?;
+
+    if result.rows_affected() == 0 {
+        return Err(AppError::NotFound);
+    }
+
+    Ok(StatusCode::NO_CONTENT)
+}
+
 async fn delete_tutor(
    claims: TutorClaims,
    State(pool): State<SqlitePool>,
@@ -85,16 +114,243 @@ async fn delete_tutor(
        return Err(AppError::Conflict("cannot delete yourself".into()));
    }

-    sqlx::query("DELETE FROM tutors WHERE id = ?")
-        .bind(id)
-        .execute(&pool)
-        .await?;
+    // Wrap reference checks and DELETE in one transaction to avoid TOCTOU
+    let mut tx = pool.begin().await?;

+    let course_count: i64 =
+        sqlx::query_scalar("SELECT COUNT(*) FROM tutor_courses WHERE tutor_id = ?")
+            .bind(id)
+            .fetch_one(&mut *tx)
+            .await?;
+    if course_count > 0 {
+        return Err(AppError::Conflict(format!(
+            "Tutor:in hat noch {} Kurszuordnung(en). Bitte zuerst entfernen oder deaktivieren.",
+            course_count
+        )));
+    }
+
+    let slot_count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM slots WHERE tutor_id = ?")
+        .bind(id)
+        .fetch_one(&mut *tx)
+        .await?;
+    if slot_count > 0 {
+        return Err(AppError::Conflict(format!(
+            "Tutor:in hat noch {} Slot(s). Bitte zuerst entfernen oder deaktivieren.",
+            slot_count
+        )));
+    }
+
+    let note_count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM notes WHERE tutor_id = ?")
+        .bind(id)
+        .fetch_one(&mut *tx)
+        .await?;
+    if note_count > 0 {
+        return Err(AppError::Conflict(format!(
+            "Tutor:in hat noch {} Notiz(en). Bitte zuerst entfernen oder deaktivieren.",
+            note_count
+        )));
+    }
+
+    match sqlx::query("DELETE FROM tutors WHERE id = ?")
+        .bind(id)
+        .execute(&mut *tx)
+        .await
+    {
+        Ok(_) => {}
+        Err(sqlx::Error::Database(e)) if e.message().contains("FOREIGN KEY") => {
+            return Err(AppError::Conflict(
+                "Tutor:in hat noch Verweise in der Datenbank.".into(),
+            ));
+        }
+        Err(e) => return Err(AppError::Db(e)),
+    }
+
+    tx.commit().await?;
    Ok(StatusCode::NO_CONTENT)
 }
-
 pub fn router() -> Router<AppState> {
    Router::new()
        .route("/api/admin/tutors", get(list_tutors).post(create_tutor))
        .route("/api/admin/tutors/{id}", delete(delete_tutor))
+        .route("/api/admin/tutors/{id}/active", patch(set_tutor_active))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test_helpers::{build_test_admin_app, delete, patch_json};
+    use argon2::PasswordHasher;
+    use serde_json::json;
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn delete_tutor_with_no_refs_succeeds(pool: SqlitePool) {
+        let (app, auth) = build_test_admin_app(pool.clone()).await;
+
+        // Create a tutor to delete
+        let hash = bcrypt::hash("test", 4).unwrap();
+        let id: i64 = sqlx::query_scalar("INSERT INTO tutors (name, email, password_hash, is_superadmin, is_active) VALUES ('DeleteMe', 'del@test.com', ?, 0, 1) RETURNING id")
+            .bind(hash)
+            .fetch_one(&pool)
+            .await.unwrap();
+
+        let status = delete(app, &format!("/api/admin/tutors/{}", id), &auth)
+            .await
+            .0;
+        assert_eq!(status, StatusCode::NO_CONTENT);
+
+        let exists: bool = sqlx::query_scalar("SELECT EXISTS(SELECT 1 FROM tutors WHERE id = ?)")
+            .bind(id)
+            .fetch_one(&pool)
+            .await
+            .unwrap();
+        assert!(!exists);
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn delete_tutor_with_course_assignment_returns_409(pool: SqlitePool) {
+        let (app, auth) = build_test_admin_app(pool.clone()).await;
+
+        let id: i64 = sqlx::query_scalar("INSERT INTO tutors (name, email, password_hash, is_superadmin, is_active) VALUES ('CourseTutor', 'course@test.com', 'hash', 0, 1) RETURNING id")
+            .fetch_one(&pool).await.unwrap();
+        let course_id: i64 = sqlx::query_scalar(
+            "INSERT INTO courses (name, semester) VALUES ('FP', 'SS2026') RETURNING id",
+        )
+        .fetch_one(&pool)
+        .await
+        .unwrap();
+        sqlx::query("INSERT INTO tutor_courses (tutor_id, course_id) VALUES (?, ?)")
+            .bind(id)
+            .bind(course_id)
+            .execute(&pool)
+            .await
+            .unwrap();
+
+        let (status, body) = delete(app, &format!("/api/admin/tutors/{}", id), &auth).await;
+        assert_eq!(status, StatusCode::CONFLICT);
+        assert!(String::from_utf8_lossy(&body).contains("Kurszuordnung"));
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn delete_tutor_with_slot_returns_409(pool: SqlitePool) {
+        let (app, auth) = build_test_admin_app(pool.clone()).await;
+
+        let id: i64 = sqlx::query_scalar("INSERT INTO tutors (name, email, password_hash, is_superadmin, is_active) VALUES ('SlotTutor', 'slot@test.com', 'hash', 0, 1) RETURNING id")
+            .fetch_one(&pool).await.unwrap();
+        let course_id: i64 = sqlx::query_scalar(
+            "INSERT INTO courses (name, semester) VALUES ('FP', 'SS2026') RETURNING id",
+        )
+        .fetch_one(&pool)
+        .await
+        .unwrap();
+        let session_id: i64 = sqlx::query_scalar("INSERT INTO sessions (course_id, week_nr, date) VALUES (?, 1, '2026-05-04') RETURNING id")
+            .bind(course_id).fetch_one(&pool).await.unwrap();
+        sqlx::query("INSERT INTO slots (session_id, tutor_id, start_time, end_time, status) VALUES (?, ?, '09:00', '10:00', 'closed')")
+            .bind(session_id).bind(id).execute(&pool).await.unwrap();
+
+        let (status, body) = delete(app, &format!("/api/admin/tutors/{}", id), &auth).await;
+        assert_eq!(status, StatusCode::CONFLICT);
+        assert!(String::from_utf8_lossy(&body).contains("Slot"));
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn delete_tutor_with_note_returns_409(pool: SqlitePool) {
+        let (app, auth) = build_test_admin_app(pool.clone()).await;
+
+        let id: i64 = sqlx::query_scalar("INSERT INTO tutors (name, email, password_hash, is_superadmin, is_active) VALUES ('NoteTutor', 'note@test.com', 'hash', 0, 1) RETURNING id")
+            .fetch_one(&pool).await.unwrap();
+        let course_id: i64 = sqlx::query_scalar(
+            "INSERT INTO courses (name, semester) VALUES ('FP', 'SS2026') RETURNING id",
+        )
+        .fetch_one(&pool)
+        .await
+        .unwrap();
+        let student_id: i64 = sqlx::query_scalar(
+            "INSERT INTO students (course_id, name) VALUES (?, 'Alice') RETURNING id",
+        )
+        .bind(course_id)
+        .fetch_one(&pool)
+        .await
+        .unwrap();
+        let session_id: i64 = sqlx::query_scalar("INSERT INTO sessions (course_id, week_nr, date) VALUES (?, 1, '2026-05-04') RETURNING id")
+            .bind(course_id).fetch_one(&pool).await.unwrap();
+        let slot_id: i64 = sqlx::query_scalar("INSERT INTO slots (session_id, tutor_id, start_time, end_time, status) VALUES (?, ?, '09:00', '10:00', 'closed') RETURNING id")
+            .bind(session_id).bind(1).fetch_one(&pool).await.unwrap(); // Bind to admin
+
+        sqlx::query("INSERT INTO notes (slot_id, student_id, tutor_id, content, updated_at) VALUES (?, ?, ?, 'test', '2026-05-04T10:00:00Z')")
+            .bind(slot_id).bind(student_id).bind(id).execute(&pool).await.unwrap();
+
+        let (status, body) = delete(app, &format!("/api/admin/tutors/{}", id), &auth).await;
+        assert_eq!(status, StatusCode::CONFLICT);
+        assert!(String::from_utf8_lossy(&body).contains("Notiz"));
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn delete_self_returns_409(pool: SqlitePool) {
+        let (app, auth) = build_test_admin_app(pool.clone()).await;
+        let admin_id: i64 =
+            sqlx::query_scalar("SELECT id FROM tutors WHERE email = 'admin@test.com'")
+                .fetch_one(&pool)
+                .await
+                .unwrap();
+
+        let (status, body) = delete(app, &format!("/api/admin/tutors/{}", admin_id), &auth).await;
+        assert_eq!(status, StatusCode::CONFLICT);
+        assert!(String::from_utf8_lossy(&body).contains("cannot delete yourself"));
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn cannot_deactivate_self_returns_409(pool: SqlitePool) {
+        let (app, auth) = build_test_admin_app(pool.clone()).await;
+        let admin_id: i64 =
+            sqlx::query_scalar("SELECT id FROM tutors WHERE email = 'admin@test.com'")
+                .fetch_one(&pool)
+                .await
+                .unwrap();
+
+        let (status, body) = patch_json(
+            app,
+            &format!("/api/admin/tutors/{}/active", admin_id),
+            &auth,
+            json!({"is_active": false}),
+        )
+        .await;
+        assert_eq!(status, StatusCode::CONFLICT);
+        assert!(String::from_utf8_lossy(&body).contains("cannot deactivate yourself"));
+    }
+
+    #[sqlx::test(migrations = "./migrations")]
+    async fn set_active_false_then_login_fails(pool: SqlitePool) {
+        let (app, auth) = build_test_admin_app(pool.clone()).await;
+
+        let hash = argon2::Argon2::default()
+            .hash_password(
+                "pass".as_bytes(),
+                &argon2::password_hash::SaltString::generate(&mut rand::thread_rng()),
+            )
+            .unwrap()
+            .to_string();
+        let id: i64 = sqlx::query_scalar("INSERT INTO tutors (name, email, password_hash, is_superadmin, is_active) VALUES ('LoginFail', 'fail@test.com', ?, 0, 1) RETURNING id")
+            .bind(hash).fetch_one(&pool).await.unwrap();
+
+        // Deactivate
+        let status = patch_json(
+            app.clone(),
+            &format!("/api/admin/tutors/{}/active", id),
+            &auth,
+            json!({"is_active": false}),
+        )
+        .await
+        .0;
+        assert_eq!(status, StatusCode::NO_CONTENT);
+
+        // Attempt login
+        let (status, _) = crate::test_helpers::post_json(
+            app,
+            "/api/auth/login",
+            "",
+            json!({"email": "fail@test.com", "password": "pass"}),
+        )
+        .await;
+        assert_eq!(status, StatusCode::UNAUTHORIZED);
+    }
 }
--- a/backend/src/test_helpers.rs
+++ b/backend/src/test_helpers.rs
@@ -17,7 +17,7 @@ pub async fn make_token(
 ) -> String {
    let hash = bcrypt::hash("testpass", 4).unwrap();
    sqlx::query(
-        "INSERT OR IGNORE INTO tutors (name,email,password_hash,is_superadmin) VALUES (?,?,?,?)",
+        "INSERT OR IGNORE INTO tutors (name,email,password_hash,is_superadmin,is_active) VALUES (?,?,?,?,1)",
    )
    .bind("Test Tutor")
    .bind(email)
--- a/conductor/attendance-tool.md
+++ b/conductor/attendance-tool.md
@@ -1,161 +0,0 @@
-# Implementation Plan: Attendance Tracking Tool (Continuation)
-
-**Objective:** Complete the backend API, scaffold the SvelteKit frontend, implement all frontend views based on the provided design handoff, and set up deployment manifests. This plan picks up from where the `.worktrees/feature-tutortool` workspace left off (Tasks 1-8 completed).
-
-**Scope:**
- Complete backend APIs for attendance, notes, and exports.
- Serve SvelteKit SPA fallback via Axum.
- Scaffold SvelteKit frontend.
- Implement UI pages for Admin tools (Dashboard, Courses, Rooms, Sessions, Attendance, Notes, Export) and Student Check-in.
- Configure local development (Makefile, Docker Compose) and K8s manifests.
-
---
-
-## 1. Backend Completion
-
-### Task 9: Admin Attendance & Notes APIs
-**Files to Create/Modify:**
- `backend/src/routes/attendance.rs`
- `backend/src/routes/notes.rs`
-
-**Implementation Steps:**
- Add `POST /api/admin/slots/:id/attendance` (manual entry) and `DELETE /api/admin/slots/:slot_id/attendance/:student_id`.
- Add `GET /api/admin/sessions/:id/attendance` (per-week matrix) and `GET /api/admin/students/:id/attendance`.
- Add `PUT /api/admin/slots/:slot_id/notes/:student_id` (upsert note).
- Add `GET /api/admin/slots/:slot_id/notes` and `GET /api/admin/students/:id/notes`.
- Write corresponding unit tests.
-
-### Task 10: Export API
-**Files to Create/Modify:**
- `backend/src/routes/export.rs`
-
-**Implementation Steps:**
- Add `GET /api/admin/export/session/:id/csv` and `/md` (merged per-session weekly attendance).
- Add `GET /api/admin/export/course/:id/csv` and `/md` (full course matrix with Bonus points calculation: +3 if unexcused absences <= 1).
- Add `GET /api/admin/backup` (using `VACUUM INTO '/tmp/backup-<timestamp>.sqlite'` then streaming as `application/octet-stream`).
- Ensure all endpoints verify `TutorClaims` and course access.
-
-### Task 11: Static File Serving & Route Assembly
-**Files to Modify:**
- `backend/src/main.rs`
- `backend/src/routes/mod.rs`
-
-**Implementation Steps:**
- Merge `attendance`, `notes`, and `export` routers in `routes/mod.rs`.
- Configure `tower_http::services::ServeDir` in `main.rs` to serve the SvelteKit static build.
- Set up `ServeFile::new(format!("{static_dir}/index.html"))` as the SPA fallback service.
-
---
-
-## 2. Frontend Development
-
-### Task 12: Scaffold SvelteKit Frontend
-**Files to Create/Modify:**
- `frontend/package.json`, `svelte.config.js`, `vite.config.ts`, `src/app.html`, `src/lib/types.ts`, `src/lib/api.ts`, `src/lib/auth.ts`
-
-**Implementation Steps:**
- Initialize SvelteKit with `@sveltejs/adapter-static` configured for SPA fallback.
- Setup Vite proxy `/api` -> `http://localhost:3000`.
- Create TypeScript types mirroring the backend database models.
- Implement API client fetch wrapper (`api.ts`).
- Set up Svelte store for JWT auth (`auth.ts`).
-
-### Task 13: Login Page & Admin Auth Guard
-**Files to Create/Modify:**
- `frontend/src/routes/login/+page.svelte`
- `frontend/src/routes/admin/+layout.svelte`
-
-**Implementation Steps:**
- Implement the tutor login form and API integration.
- Protect `/admin` routes using an `onMount` check redirecting unauthenticated users to `/login`.
-
-### Task 14: Dashboard & Slot Management
-**Files to Create/Modify:**
- `frontend/src/routes/admin/+page.svelte`
-
-**Implementation Steps:**
- Display all sessions/slots.
- Implement toggles for slot status (`closed`, `open`, `locked`).
- Display check-in link and copy button when a slot is `open`.
-
-### Task 15: Courses & Students UI
-**Files to Create/Modify:**
- `frontend/src/routes/admin/courses/+page.svelte`
-
-**Implementation Steps:**
- List courses and forms to create new courses.
- Per-course student management: list students, add individual student, import from CSV, and delete students.
-
-### Task 16: Room Layout Editor
-**Files to Create/Modify:**
- `frontend/src/lib/RoomCanvas.svelte`
- `frontend/src/routes/admin/rooms/+page.svelte`
-
-**Implementation Steps:**
- Implement SVG-based `RoomCanvas.svelte` supporting interactive (draggable/editable) mode, student check-in mode, and tutor notes mode.
- Build room management UI: list rooms, create rooms, and edit JSON room layouts visually.
-
-### Task 17: Sessions & Slots UI
-**Files to Create/Modify:**
- `frontend/src/routes/admin/sessions/+page.svelte`
-
-**Implementation Steps:**
- Form to create sessions (course, week_nr, date).
- Form to add slots within a session (room, tutor, start_time, end_time).
-
-### Task 18: Student Check-in Page
-**Files to Create/Modify:**
- `frontend/src/routes/s/[code]/+page.svelte`
-
-**Implementation Steps:**
- Fetch slot info. If no identity cookie exists, show name dropdown filtered to the course.
- Display `RoomCanvas` indicating free/occupied seats.
- Handle FCFS seat locking API calls (`POST /api/checkin`) and update UI.
- Support read-only mode for locked/closed slots.
-
-### Task 19: Attendance & Notes UI
-**Files to Create/Modify:**
- `frontend/src/routes/admin/attendance/+page.svelte`
- `frontend/src/routes/admin/notes/+page.svelte`
-
-**Implementation Steps:**
- Build matrix tables (per-week and per-student) for manual attendance marking/removal.
- Build notes UI utilizing `RoomCanvas` for clicking on seats to leave inline text notes.
-
-### Task 20: Export UI
-**Files to Create/Modify:**
- `frontend/src/routes/admin/export/+page.svelte`
-
-**Implementation Steps:**
- Provide buttons to download weekly CSV/Markdown, full course matrix, and SQLite backup directly from the admin interface.
-
---
-
-## 3. DevOps & Deployment
-
-### Task 21: Local Dev Environment
-**Files to Create/Modify:**
- `Makefile`
- `docker-compose.yml`
-
-**Implementation Steps:**
- Write `Makefile` with commands: `dev`, `dev-backend`, `dev-frontend`, `test`, `build`, `compose-up`.
- Create `docker-compose.yml` for testing the production image locally using SQLite mounted via volume.
-
-### Task 22: Dockerfile & K8s Manifests
-**Files to Create/Modify:**
- `Dockerfile`
- `k8s/deployment.yaml`, `k8s/service.yaml`, `k8s/ingress.yaml`, `k8s/pvc.yaml`, `k8s/cronjob.yaml`
-
-**Implementation Steps:**
- Write a 3-stage `Dockerfile` (frontend build, backend build, alpine + sqlite runtime).
- Write `pvc.yaml` for SQLite persistent storage.
- Write `deployment.yaml`, `service.yaml`, and `ingress.yaml` (`tutor.puchstein.dev`).
- Write `cronjob.yaml` running at 3 AM daily, executing `sqlite3 /data/attendance.db "VACUUM INTO '/data/backup-$(date +%F).sqlite'"` and pruning files older than 7 days.
-
---
-
-## Verification Strategy
-1. **Unit Tests:** Execute `cargo test` in `backend/` to verify all new endpoints (Tasks 9-11).
-2. **End-to-End Test:** Start `make dev` and manually verify all critical paths: tutor login, session/slot creation, student check-in with cookie persistence, FCFS seat collision handling, manual attendance, and exporting.
-3. **Deployment Test:** Run `make compose-up` to ensure the built Docker container operates as expected, serving Svelte SPA fallback via Axum properly.
--- a/conductor/demo-plan.md
+++ b/conductor/demo-plan.md
@@ -1,39 +0,0 @@
-# Demo Preparation & Seed Data Plan
-
-## Objective
-Create an isolated, reproducible demo environment for presenting TutorTool on a Surface Pro 5 (Arch Linux) using Docker. This includes a robust set of seed data to simulate a live application state, which can also be utilized for local end-to-end testing.
-
-## Key Files & Context
- **Environment**: `docker-compose.yml` (existing)
- **Database**: SQLite (`data/attendance.db`)
- **New Files**:
-  - `backend/migrations/demo_seed.sql`: A standalone SQL script containing isolated test data.
- **Modified Files**:
-  - `Makefile`: Update to include a `seed-demo` target for easy execution.
-
-## Implementation Steps
-
-### 1. Workspace Isolation via Git Worktree
-When implementing this plan, the Gemini CLI will automatically utilize its Git worktree feature to spawn a new isolated workspace (e.g., `feature/demo-seed`). This ensures the backend tooling modifications do not interfere with the `frontend-design-overhaul` worktree or the main branch.
-
-### 2. Create the Seed Data Script (`backend/migrations/demo_seed.sql`)
-Create a SQL script that safely injects realistic demo data. It will use `INSERT OR IGNORE` or handle conflicts to ensure it can be run cleanly for both demo and testing purposes.
- **Admin/Tutor Account**: 
-  - Name: "Demo Admin"
-  - Email: `admin@tutortool.com`
-  - Password Hash: A pre-calculated bcrypt hash for the password `admin`.
- **Course**: "Demo Course 101" (Semester: "Current").
- **Room Layout**: A valid JSON SVG layout representing a small classroom with a few tables and seats.
- **Students**: Generate ~10 distinct student names linked to the course.
- **Session & Slot**: Create a session for the current date and an "open" slot linked to the demo room, ensuring the check-in feature can be demonstrated immediately without setup.
-
-### 3. Update Makefile
-Add a `seed-demo` target to the existing `Makefile`.
- The target will execute the SQLite CLI to run `demo_seed.sql` against the local development database defined by the `DATABASE_URL` environment variable (defaulting to `sqlite:./dev.db` for local dev).
-
-### 4. Demo Run Guide
-Provide a short set of instructions on how to start the environment using `docker-compose up` and the new seed command on the Surface Pro 5.
-
-## Verification & Testing
- **Execution**: Run `make seed-demo` against a fresh SQLite database to ensure no foreign key or syntax errors occur.
- **Authentication**: Verify that logging in with `admin@tutortool.com` / `admin` succeeds against the seeded database.
--- a/conductor/fix-playwright-mcp-config.md
+++ b/conductor/fix-playwright-mcp-config.md
@@ -1,13 +0,0 @@
-# Objective
-Fix the Playwright MCP configuration in Gemini CLI by aligning it with the working Claude Code configuration.
-
-# Key Files & Context
- `.gemini/settings.json`: This file currently contains the incorrect configuration pointing to `/opt/google/chrome/chrome`.
-
-# Implementation Steps
-1. Update `.gemini/settings.json` to modify the `args` array for the `playwright` mcpServer.
-2. Remove the `--browser` and `chrome` arguments.
-3. Update `--executable-path` to point to `/home/mpuchstein/.cache/ms-playwright/chromium-1208/chrome-linux64/chrome` (the working binary used by Claude).
-
-# Verification & Testing
-After updating the configuration, the user will need to restart the Gemini CLI session to apply the changes and verify that the Playwright MCP tools function correctly.
--- a/conductor/superadmin-crud.md
+++ b/conductor/superadmin-crud.md
@@ -1,56 +0,0 @@
-# Superadmin CRUD Implementation Plan
-
-**Objective:** Implement a superadmin role to manage courses and tutors, ensuring only authorized users can perform system-wide administrative actions. This feature will be developed in an isolated git worktree.
-
-## Key Context & Decisions
- **Role Strategy:** A new `is_superadmin` boolean column will be added to the `tutors` database table.
- **UI Structure:** A dedicated `/admin/tutors` page will handle tutor management. Course management will remain on `/admin/courses` but will be enhanced with superadmin-only actions (e.g., assigning tutors to courses).
- **Workspace:** Development will be done in `.worktrees/feature-superadmin-crud`.
-
-## Implementation Steps
-
-### 1. Workspace Isolation via Git Worktree
- Create a new git worktree: `git worktree add .worktrees/feature-superadmin-crud -b feature-superadmin-crud`
- All subsequent steps will be performed inside this isolated workspace.
-
-### 2. Database & Models
- Create migration `backend/migrations/002_add_superadmin.sql` to add `is_superadmin BOOLEAN NOT NULL DEFAULT 0` to the `tutors` table.
- Update `backend/demo/demo_seed.sql` to set the default `admin@tutortool.com` as a superadmin (`is_superadmin = 1`).
- Update `backend/src/models.rs` to include `is_superadmin: bool` in the `Tutor` struct.
- Add `CreateTutor` and `TutorResponse` structs to `backend/src/models.rs`.
-
-### 3. Auth & Core Backend
- Modify `backend/src/auth.rs` to include `is_superadmin: bool` in `TutorClaims`. This allows auth guards to check permissions efficiently.
- Update `backend/src/routes/auth_routes.rs` login handler to fetch `is_superadmin` and encode it in the JWT.
- Add a helper function to verify superadmin access to reject unauthorized requests.
-
-### 4. Tutors API
- Create `backend/src/routes/tutors.rs` with endpoints:
-  - `GET /api/admin/tutors` (list all tutors)
-  - `POST /api/admin/tutors` (create a tutor, hashing their password)
-  - `DELETE /api/admin/tutors/:id` (delete a tutor)
- Merge these routes in `backend/src/routes/mod.rs`.
-
-### 5. Course Assignments API
- Modify `backend/src/routes/courses.rs`:
-  - Enhance `GET /api/admin/courses` to return ALL courses if `claims.is_superadmin` is true, otherwise only return assigned courses.
-  - Restrict `POST /api/admin/courses` to superadmins only.
-  - Add `POST /api/admin/courses/:id/tutors` to assign a tutor to a course (superadmin only).
-  - Add `DELETE /api/admin/courses/:id/tutors/:tutor_id` to remove a tutor from a course (superadmin only).
-  - Add `GET /api/admin/courses/:id/tutors` to list tutors assigned to a course.
-
-### 6. Frontend Auth & API Client
- Update `frontend/src/lib/types.ts` to include `Tutor` and the new `is_superadmin` flag in token payload or state.
- Add the new endpoints to `frontend/src/lib/api.ts` under `api.admin.tutors` and enhance `api.admin.courses`.
-
-### 7. Frontend UI: Tutors Management
- Update `frontend/src/lib/components/TutorShell.svelte` to conditionally render a "Tutor:innen" link in the sidebar if the user is a superadmin.
- Create `frontend/src/routes/admin/tutors/+page.svelte` following the paper-bg design system. Include a list of tutors and a form to add a new tutor.
-
-### 8. Frontend UI: Courses Enhancements
- Modify `frontend/src/routes/admin/courses/+page.svelte` to show a "Tutor:innen zuweisen" (Assign Tutors) section for each course if the logged-in user is a superadmin.
- Restrict the course creation form to superadmins only.
-
-## Verification & Testing
- Run `cargo test` in the backend to ensure existing tests pass and new route isolation works.
- Perform a manual end-to-end test using the `make dev` script in the new worktree to verify the UI.
--- a/deploy/templates/cronjob-backup.yaml
+++ b/deploy/templates/cronjob-backup.yaml
@@ -7,12 +7,22 @@ metadata:
    {{- include "tutortool.labels" . | nindent 4 }}
 spec:
  schedule: "0 3 * * *"
+  concurrencyPolicy: Forbid
  successfulJobsHistoryLimit: 1
+  failedJobsHistoryLimit: 1
  jobTemplate:
    spec:
+      activeDeadlineSeconds: 900
      template:
        spec:
          restartPolicy: OnFailure
+          affinity:
+            podAffinity:
+              requiredDuringSchedulingIgnoredDuringExecution:
+                - labelSelector:
+                    matchLabels:
+                      {{- include "tutortool.selectorLabels" . | nindent 22 }}
+                  topologyKey: kubernetes.io/hostname
          containers:
            - name: backup
              image: alpine:latest
--- a/docs/issues_discovered_20260504.md
+++ b/docs/issues_discovered_20260504.md
@@ -0,0 +1,40 @@
+# Issues Discovered - 2026-05-04
+
+This document summarizes the issues found during the Playwright exploration session on 2026-05-04.
+
+## 1. JSON Parse Error when adding Tutors to Courses
+- **Location**: `frontend/src/routes/admin/courses/+page.svelte` (triggered by `api.admin.courses.addTutor`)
+- **Symptoms**: Alert box shows `SyntaxError: Failed to execute 'json' on 'Response': Unexpected end of JSON input`.
+- **Root Cause**: The backend `POST /api/admin/courses/:id/tutors` handler likely returns a `200 OK` with an empty body. The frontend `api.ts` wrapper attempts to call `.json()` on every response, which fails on empty bodies.
+- **Evidence**: Network request #48 in Playwright session showed `status: 200` but `content-length: 0`.
+
+## 2. Attendance Count Missing on Student Check-in Page
+- **Location**: `frontend/src/routes/s/[code]/+page.svelte`
+- **Symptoms**: The "Anwesende" count shows `0 / 11` even after a successful check-in or when other students are present.
+- **Root Cause**: The `loadInfo` function fetches the data but never assigns `res.attendances` to the local `attendances` state variable.
+- **Evidence**: `loadInfo` contains `const checkinAttendances = res.attendances ?? [];` but lacks `attendances = checkinAttendances;`.
+
+## 3. Seat Map Empty in Live View
+- **Location**: `frontend/src/routes/admin/live/[slotId]/+page.svelte`
+- **Symptoms**: All seats show as "frei" in the tutor's live view, even when students are checked in and assigned to seats.
+- **Root Cause**: The `SeatMap` component is instantiated without passing `assignments` or `students` props.
+- **Evidence**: `<SeatMap variant="tutor" scale={0.78} />` is used without other props in the source code.
+
+## 4. Room Editor Element Selection Broken
+- **Location**: `frontend/src/lib/RoomCanvas.svelte`
+- **Symptoms**: Clicking an element in the Room Layout Editor does not select it (sidebar continues to show "Element auswählen").
+- **Root Cause**: In `handleMouseDown`, if `editable` is true, the function returns early without calling `onElementClick`.
+- **Evidence**: 
+  ```typescript
+  function handleMouseDown(e: MouseEvent, el: LayoutElement) {
+      if (!editable) {
+          onElementClick?.(el);
+          return;
+      }
+      draggingId = el.id;
+      // ...
+  }
+  ```
+
+## 5. Potential UI/UX: Dashboard Slot Status
+- **Observation**: Dashboard sometimes shows "Anwesenheit offen" but "Alle Slots 1" and "Abgeschlossene Slots 0". It's a bit confusing if there is only one slot ever. (Minor)
--- a/docs/plans/2026-05-04-unified-fixes-and-room-editor-refactor.md
+++ b/docs/plans/2026-05-04-unified-fixes-and-room-editor-refactor.md
@@ -0,0 +1,263 @@
+# TutorTool — Unified Bug Fixes, Tutor Lifecycle, Room Editor Refactor
+
+## Context
+
+A Playwright exploration session on **2026-05-04** (`docs/issues_discovered_20260504.md`) surfaced four production frontend bugs on top of an existing security backlog (RUSTSEC-2023-0071) and a half-finished Room Editor refactor. Three reference plans already exist in `conductor/`:
+
+- `conductor/room-editor-refactor-core.md` — pixel→grid migration + editor robustification
+- `conductor/room-editor-refactor-visualization.md` — replace hardcoded `SeatMap.svelte` with dynamic `RoomCanvas`
+- `conductor/unified-refactor-and-fixes.md` — already merges the above with security/quick fixes (RUSTSEC, JSON parse, check-in typing, admin logout)
+
+This plan **supersedes** `conductor/unified-refactor-and-fixes.md`, folds in two newly verified items:
+
+1. **Admin/tutor deletion is opaquely broken.** `DELETE /api/admin/tutors/{id}` exists (`backend/src/routes/tutors.rs:74-94`) but the three FK references — `tutor_courses.tutor_id`, `slots.tutor_id`, `notes.tutor_id` (`backend/migrations/001_initial.sql:15,44,65`) — declare no `ON DELETE` clause, so SQLite RESTRICT raises a generic FK error → 500 → `alert("internal error")`.
+2. **Issue #4 in the discovered-issues doc has its condition inverted.** `frontend/src/lib/RoomCanvas.svelte:30-38` is `if (!editable) { onElementClick?.(el); return; }`, so click-to-select fails **in edit mode** (the opposite of what the doc says). Fix: in edit mode, also fire `onElementClick` before initiating the drag.
+
+The intended outcome is one continuous batch of work that ships: secure auth (logout + RUSTSEC patch), correct frontend data flow, a real tutor lifecycle (deactivate + delete with safety), and a unified, dynamic room renderer that fixes the silently-broken student check-in.
+
+> **Memory housekeeping (post-approval):** the SLM memory `1728144c207346e2` ("admin CRUD enforces a permanent restriction: no tutors can be deleted") is **stale and contradicted by the code**. Update or remove it after this plan is approved.
+
+---
+
+## Phase 0 — Git Workflow
+
+### 0.1 Create a worktree
+
+From your main clone (assume it lives at `~/tutortool`):
+
+```sh
+git worktree add ../tutortool-unified main
+cd ../tutortool-unified
+git switch -c feature/unified-fixes-room-editor
+```
+
+All implementation work happens in `../tutortool-unified`.
+The original clone stays clean on `main`.
+
+### 0.2 Commit discipline
+
+- One logical commit per Phase/sub-phase, e.g.:
+  - `feat(security): fix RUSTSEC-2023-0071 via aws_lc_rs`
+  - `fix(api): handle empty 200 body + fix check-in typing`
+  - `feat(tutors): add is_active flag, deactivate + safe delete`
+  - `feat(rooms): pixel→grid migration + layout validators`
+  - `feat(canvas): fix drag/resize, click-to-select in edit mode`
+  - `feat(viz): replace SeatMap with dynamic RoomCanvas`
+- `make lint && make test` must pass **before** each commit.
+  Gate with a pre-commit hook if you like:
+  ```sh
+  # .git/hooks/pre-commit
+  #!/bin/sh
+  cd backend && cargo clippy --all-targets -- -D warnings && cargo test
+  ```
+
+### 0.3 Open the PR
+
+Once all phases are done and CI is green:
+
+```sh
+git push -u origin feature/unified-fixes-room-editor
+# then open a PR against main via Gitea/GitHub UI
+# title: "Unified fixes, tutor lifecycle, room editor refactor"
+# body: link this plan doc, list phases, reference Playwright spec results
+```
+
+Merge strategy: **squash-merge** each phase-branch if you split work, or a single **merge commit** if working on one branch (keeps phase history readable).
+
+### 0.4 Post-merge cleanup
+
+```sh
+cd ~/tutortool          # back to main clone
+git pull               # fast-forward to merged state
+git worktree remove ../tutortool-unified
+git branch -d feature/unified-fixes-room-editor
+```
+
+### 0.5 Verification gate before merge
+
+PR must have:
+
+- [ ] `make test` passes (all backend + new Phase 2.4/3.2/3.7 tests)
+- [ ] `make lint` passes (zero Clippy warnings, zero TS errors)
+- [ ] `sqlx migrate run` clean on fresh DB (migrations 003 + 004)
+- [ ] All new Playwright specs green (`rooms`, `checkin-dynamic`, `admin-live-dynamic`, `admin-tutors`, `admin-rooms-delete`)
+- [ ] `cargo audit` clean (no RUSTSEC-2023-0071)
+
+## Phase 1 — Security & Quick Fixes
+
+### 1.1 RUSTSEC-2023-0071 (Marvin Attack)
+
+- `backend/Cargo.toml` — set `jsonwebtoken` to `features = ["aws_lc_rs"]`.
+- `backend/audit.toml` — remove `ignore = ["RUSTSEC-2023-0071"]`.
+- `.gitea/workflows/ci.yml` and `.gitea/workflows/release.yml` — drop `--ignore RUSTSEC-2023-0071`.
+
+### 1.2 JSON parse error on empty 200 body
+
+- `frontend/src/lib/api.ts:46` — currently only 204 is short-circuited. Extend the empty-body branch to also handle 200-with-empty-body (probe `content-length === '0'` or fall through `await res.text()` and return `{} as T` if empty). Triggers from `assignTutor`, `unassignTutor`, etc.
+
+### 1.3 Check-in API typing
+
+- `frontend/src/lib/api.ts` — `checkin.post` currently typed `Promise<Attendance>`; backend returns `{ok: true}`. Change to `Promise<{ok: boolean}>`.
+- `frontend/src/routes/s/[code]/+page.svelte:82` — drop the local-state assignment from the response; rely on the subsequent `loadInfo()` to populate `myAttendance`.
+
+### 1.4 Attendance count not assigned (issues doc #2)
+
+- `frontend/src/routes/s/[code]/+page.svelte` `loadInfo` — assign `attendances = checkinAttendances` so the "Anwesende N / M" counter updates.
+
+### 1.5 Admin logout UI
+
+- `frontend/src/lib/components/TutorShell.svelte` (where the actual sidebar nav lives — `frontend/src/routes/admin/+layout.svelte` only renders the shell) — add an "Abmelden" entry at the bottom of the nav. On click: `await api.auth.logout()` → `auth.logout()` → `goto('/admin/login')`. Re-export `auth` and `api` if needed.
+
+---
+
+## Phase 2 — Tutor Lifecycle: Deactivate **and** Delete
+
+The user wants **both** soft-deactivate (preserve history, hide from pickers) **and** real hard-delete (with safety pre-check).
+
+### 2.1 Schema migration
+
+- New file `backend/migrations/004_tutor_is_active.sql`:
+  ```sql
+  ALTER TABLE tutors ADD COLUMN is_active BOOLEAN NOT NULL DEFAULT 1;
+  ```
+  No backfill needed; existing rows default to active.
+
+### 2.2 Backend changes
+
+**File:** `backend/src/routes/tutors.rs`
+
+- **`Tutor` model** (`backend/src/models.rs:11-17`) — add `is_active: bool`.
+- **`list_tutors`** — include `is_active` in SELECT and JSON output. Do **not** filter; the admin needs to see inactive tutors to reactivate them.
+- **New: `set_tutor_active(id, {is_active: bool})`** — `PATCH /api/admin/tutors/{id}/active` body `{is_active: bool}`. Superadmin-only. Forbid self-deactivation (mirror the self-delete guard at `tutors.rs:84-86` — return `AppError::Conflict("cannot deactivate yourself")`).
+- **`delete_tutor`** (existing handler) — before the `DELETE FROM tutors`, run three `SELECT COUNT(*)` queries inside a single connection (no need for an explicit tx; SQLite SELECTs see committed state):
+  - `tutor_courses WHERE tutor_id = ?`
+  - `slots WHERE tutor_id = ?`
+  - `notes WHERE tutor_id = ?`
+    If any non-zero, return `AppError::Conflict(format!("Tutor:in hat noch {c} Kurszuordnung(en), {s} Slot(s) und {n} Notiz(en). Bitte zuerst entfernen oder deaktivieren."))`.
+
+  `AppError::Conflict` already maps to 409 with `{"error": msg}` (`backend/src/error.rs`).
+
+- **Auth login** (`backend/src/routes/auth_routes.rs:22-96`) — reject inactive tutors with `AppError::Unauthorized` (same response shape as wrong-password to avoid info leakage). Add this check after password verification.
+- **Tutor pickers** — grep for `SELECT … FROM tutors` outside of `list_tutors` and `auth_routes.rs`. Likely sites: `backend/src/routes/courses.rs` (tutor assignment list), `backend/src/routes/sessions.rs` or `slots` creation flow. Each must add `WHERE is_active = 1`.
+
+### 2.3 Frontend changes
+
+**File:** `frontend/src/routes/admin/tutors/+page.svelte`
+
+- Show three status pills: `Superadmin` / `Tutor:in` / `Inaktiv` (combine `is_superadmin` + `is_active`).
+- Add a per-row "Deaktivieren" button (or "Aktivieren" if already inactive) that calls `api.admin.tutors.setActive(id, !is_active)`.
+- Keep the existing "Löschen" button — error message from 409 already surfaces via the existing `catch (err) { alert(err.message) }` because `request<T>` extracts `error.error` (`api.ts:42-43`). Optionally: replace alert with an inline error region above the table for better UX.
+- **API client** `frontend/src/lib/api.ts` — add `api.admin.tutors.setActive(id, is_active)` calling `PATCH /admin/tutors/{id}/active`.
+
+### 2.4 Tests (`backend/src/routes/tutors.rs` `#[cfg(test)]` block)
+
+Pattern after `backend/src/routes/rooms.rs:184-322` and use `backend/src/test_helpers.rs`.
+
+- `delete_tutor_with_no_refs_succeeds` → 204, row gone.
+- `delete_tutor_with_course_assignment_returns_409` → body contains `Kurszuordnung`.
+- `delete_tutor_with_slot_returns_409` → body contains `Slot`.
+- `delete_tutor_with_note_returns_409` → body contains `Notiz`.
+- `delete_self_returns_409` (existing branch coverage).
+- `set_active_false_then_login_fails` — deactivate, attempt login, expect 401.
+- `set_active_false_hides_from_pickers` — verify any tutor-picker endpoint doesn't list inactive tutors.
+- `cannot_deactivate_self_returns_409`.
+
+---
+
+## Phase 3 — Room Editor Core
+
+Reference: `conductor/room-editor-refactor-core.md`. One-liner per task:
+
+- **3.1 Pixel→grid migration** — new `backend/migrations/003_normalize_room_layout_units.sql`: parse `layout_json` per row; if any of x/y/w/h > 50, divide all four by 40 and rewrite. Update `backend/demo/demo_seed.sql:16-41` to grid units. Update any `rooms.rs` tests asserting pixel-scale numbers.
+  - **Note on numbering:** this is migration `003`; tutor `is_active` is `004`. Apply order matters because `003` only touches `rooms`, `004` only touches `tutors` — no cross-dependency.
+- **3.2 Additive layout validators** — `backend/src/routes/rooms.rs:18-69`: add `MAX_CANVAS = 100` upper-bound + 0.5-step multiple checks; one test per validator.
+- **3.3 RoomCanvas drag/resize hardening** — `frontend/src/lib/RoomCanvas.svelte`: bind `mousemove`/`mouseup` to `window` while dragging (currently bound to SVG only at lines 69-71); build resize handles + state from scratch; default snap step 0.5 (configurable via `snapStep` prop).
+- **3.4 Fix click-to-select in edit mode (issues #4 corrected)** — `frontend/src/lib/RoomCanvas.svelte:30-38`: when `editable`, still call `onElementClick?.(el)` (so the parent updates `selectedId`) before starting the drag. Do **not** early-return.
+- **3.5 Editor UI improvements** — `frontend/src/routes/admin/rooms/[roomId]/+page.svelte`: add X/Y `step="0.5"` numeric inputs, "+ Gap" button, "Snap to Grid" toggle, "Duplicate element" (UUID + 1-unit offset), inline error region for `saveLayout` failures (currently only `console.error`).
+- **3.6 Robust seat labelling** — same file: replace the brittle `(filter + 1)` next-label with `max(existingLabels) + 1`.
+- **3.7 Room and Element deletion**
+  - **Element deletion** is already wired in the editor sidebar (`+page.svelte:101`); validate it still works post-migration.
+  - **Room deletion (new)**:
+    - Backend: `DELETE /api/admin/rooms/{id}` in `backend/src/routes/rooms.rs`. Pre-check `SELECT COUNT(*) FROM slots WHERE room_id = ?`; if non-zero, 409 with `format!("Raum hat noch {n} Slot(s). Bitte zuerst entfernen.")`. Otherwise plain DELETE.
+    - Frontend: `frontend/src/routes/admin/rooms/+page.svelte` — add per-row "Löschen" button with `confirm()` dialog; error message surfaces via the existing alert path.
+    - API client: `api.admin.rooms.delete(id)`.
+    - Tests: `delete_room_with_no_slots_succeeds`, `delete_room_with_slot_returns_409`.
+
+---
+
+## Phase 4 — Unified Visualization (Dynamic RoomCanvas)
+
+Reference: `conductor/room-editor-refactor-visualization.md`. One-liner per task:
+
+- **4.1 Extend RoomCanvas** — `frontend/src/lib/RoomCanvas.svelte`: add `clickable: boolean = false` prop (orthogonal to 3.4 — `clickable` enables `onElementClick` in **read-only** mode); replace fixed `width="800" height="600"` (line 65) with computed `viewBox` + `preserveAspectRatio="xMidYMid meet"` + CSS `width:100%;height:auto`; verify the editor route still bounds the SVG (wrap with `style="width:800px"` if needed); apply seat/table styling from the design handoff (rounded tables, occupied/mine colour states, label positioning).
+- **4.2 Backend: ship layout with attendance** — `backend/src/routes/attendance.rs:62-105` + `backend/src/models.rs`: extend `SessionAttendance` with per-slot `layout: Option<Vec<LayoutElement>>` to avoid an N+1.
+- **4.3 Admin live view migration** — `frontend/src/routes/admin/live/[slotId]/+page.svelte:161`: replace `<SeatMap variant="tutor" scale={0.78} />` with `<RoomCanvas elements={slot.layout ?? []} clickable occupiedSeatIds={…} studentNames={…} onElementClick={handleSeatClick} />`. Implement `handleSeatClick(seatId)` mapping seat→student via `attendances.find(a => a.seat_id === seatId)?.student_id` → `selectedStudentId` (drives the existing note editor).
+- **4.4 Student check-in migration (4 sites)** — `frontend/src/routes/s/[code]/+page.svelte` lines 210, 248, 316, 368: read `res.layout` in `loadInfo` (`let layout = $state<LayoutElement[]>([])`); replace each call. Lines 210/316 (seat-pick): `clickable` + `onElementClick={selectSeat}`. Lines 248/368 (confirmed): read-only with `mySeatId={myAttendance?.seat_id ?? null}`. Add `const occupiedSeatIds = $derived(attendances.map(a => a.seat_id).filter(Boolean) as string[])`.
+- **4.5 Delete `frontend/src/lib/components/SeatMap.svelte`** — only after `grep -rn "SeatMap" frontend/src/` returns zero hits and Playwright passes.
+
+---
+
+## Verification
+
+### Automated
+
+- `make test` — backend suite passes, including:
+  - Phase 2.4 tutor delete + activate tests
+  - Phase 3.2 layout validator tests
+  - Phase 3.7 room delete tests
+- `sqlx migrate run` against a clean DB — migrations 003 and 004 apply cleanly.
+- `make lint` — zero warnings (per the project's mandate).
+- `frontend/tests/rooms.spec.ts` _(new)_ — create room, drag/snap, save/reload, assert coords preserved.
+- `frontend/tests/checkin-dynamic.spec.ts` _(new)_ — custom layout, click seat, `POST /api/checkin` succeeds, seat turns green.
+- `frontend/tests/admin-live-dynamic.spec.ts` _(new)_ — student appears on correct seat in tutor live view.
+- `frontend/tests/admin-tutors.spec.ts` _(new)_ — (i) delete tutor with no refs → row disappears; (ii) delete tutor attached to a course → red error mentions `Kurszuordnung`; unassign → retry succeeds; (iii) deactivate → tutor cannot log in; (iv) reactivate → tutor can log in again.
+- `frontend/tests/admin-rooms-delete.spec.ts` _(new)_ — delete unused room succeeds; delete room attached to a slot → 409 message visible.
+
+### Manual
+
+1. `make seed-demo`. Open `Admin → Rooms → Room A` — all elements at sensible grid positions (no values > 50).
+2. Drag and resize an element; release outside the SVG; confirm no stranded drag.
+3. Click an element in **edit mode** — sidebar populates (issue #4 regression).
+4. Add a Gap; toggle Snap; Duplicate an element; trigger a deliberate save error and confirm the inline message.
+5. Create a U-shaped room; attach to a session/slot.
+6. Open the student check-in link on a mobile viewport — U-shape renders, seat-click checks in, seat turns green.
+7. Open tutor Live View — student name on correct seat; click opens note editor.
+8. **Tutor lifecycle:** as superadmin, create a tutor "Test", attach to a course → click `Löschen` → red message lists `1 Kurszuordnung`. Click `Deaktivieren` → status pill flips to `Inaktiv`; attempt to log in as that tutor → fails. Click `Aktivieren` → login succeeds again. Unassign from course → click `Löschen` → succeeds.
+9. **Room lifecycle:** delete a room with no slots → row disappears. Delete a room attached to a slot → 409 message visible.
+10. Click `Abmelden` in admin sidebar → redirect to `/admin/login`; refresh → still logged out.
+11. `cargo audit` (without the ignore flag) — no RUSTSEC-2023-0071 finding.
+
+---
+
+## Critical files
+
+- `backend/Cargo.toml`
+- `backend/audit.toml`
+- `.gitea/workflows/ci.yml`, `.gitea/workflows/release.yml`
+- `backend/migrations/003_normalize_room_layout_units.sql` _(new)_
+- `backend/migrations/004_tutor_is_active.sql` _(new)_
+- `backend/demo/demo_seed.sql`
+- `backend/src/models.rs`
+- `backend/src/routes/tutors.rs`
+- `backend/src/routes/rooms.rs`
+- `backend/src/routes/attendance.rs`
+- `backend/src/routes/auth_routes.rs`
+- `backend/src/routes/courses.rs` (tutor picker filter)
+- `backend/src/routes/sessions.rs` (tutor picker filter)
+- `frontend/src/lib/api.ts`
+- `frontend/src/lib/types.ts`
+- `frontend/src/lib/RoomCanvas.svelte`
+- `frontend/src/lib/components/SeatMap.svelte` _(delete in Phase 4.5)_
+- `frontend/src/lib/components/TutorShell.svelte` (logout button)
+- `frontend/src/routes/admin/tutors/+page.svelte`
+- `frontend/src/routes/admin/rooms/+page.svelte`
+- `frontend/src/routes/admin/rooms/[roomId]/+page.svelte`
+- `frontend/src/routes/admin/live/[slotId]/+page.svelte`
+- `frontend/src/routes/s/[code]/+page.svelte`
+
+---
+
+## Post-implementation memory hygiene (do after the plan ships)
+
+- Update SLM memory `1728144c207346e2` to reflect the new lifecycle (deactivate + safe delete) instead of the stale "no tutors can be deleted" claim.
+- Store a new SLM memory capturing the deletion-policy decision (deactivate-or-block-with-409) so future sessions don't re-litigate it.
--- a/frontend/src/app.css
+++ b/frontend/src/app.css
@@ -80,6 +80,7 @@ body, .ui {

 .pill.open { color: var(--amber); background: rgba(176,125,42,0.08); }
 .pill.closed { color: var(--ink-3); }
+.pill.inactive { color: var(--ink-4); border-style: dashed; }
 .pill.locked { color: var(--accent); background: rgba(138,44,31,0.06); }
 .pill.present { color: var(--green); background: rgba(74,107,58,0.08); }
 .pill.absent { color: var(--accent); }
--- a/frontend/src/lib/RoomCanvas.svelte
+++ b/frontend/src/lib/RoomCanvas.svelte
@@ -4,7 +4,9 @@
    interface Props {
        elements: LayoutElement[];
        editable?: boolean;
-        onElementClick?: (el: LayoutElement) => void;
+        clickable?: boolean;
+        snapStep?: number;
+        onElementClick?: (el: LayoutElement | null) => void;
        onLayoutChange?: (elements: LayoutElement[]) => void;
        selectedId?: string | null;
        occupiedSeatIds?: string[];
@@ -15,6 +17,8 @@
    let { 
        elements = $bindable([]), 
        editable = false, 
+        clickable = false,
+        snapStep = 0.5,
        onElementClick, 
        onLayoutChange,
        selectedId = null,
@@ -24,57 +28,148 @@
    }: Props = $props();

    let draggingId = $state<string | null>(null);
+    let resizingId = $state<string | null>(null);
+    let resizeDir = $state<'e' | 's' | 'se' | null>(null);
+
    let startX = 0;
    let startY = 0;
+    let initialX = 0;
+    let initialY = 0;
+    let initialW = 0;
+    let initialH = 0;
+    let dragMoved = false;
+
+    const GRID_SIZE = 40;

    function handleMouseDown(e: MouseEvent, el: LayoutElement) {
-        if (!editable) {
+        if (clickable && !editable) {
            onElementClick?.(el);
            return;
        }
+        if (!editable) return;
+
        draggingId = el.id;
-        startX = e.clientX - el.x * 40;
-        startY = e.clientY - el.y * 40;
+        dragMoved = false;
+        startX = e.clientX;
+        startY = e.clientY;
+        initialX = el.x;
+        initialY = el.y;
+        e.stopPropagation();
    }

-    function handleMouseMove(e: MouseEvent) {
-        if (!draggingId || !editable) return;
-        const index = elements.findIndex((el: LayoutElement) => el.id === draggingId);
-        if (index === -1) return;
-        const el = elements[index];
-        if (!el) return;
-
-        const newX = Math.round((e.clientX - startX) / 10) * 10 / 40;
-        const newY = Math.round((e.clientY - startY) / 10) * 10 / 40;
-
-        elements[index] = { ...el, x: newX, y: newY };
+    function handleResizeDown(e: MouseEvent, el: LayoutElement, dir: 'e' | 's' | 'se') {
+        if (!editable) return;
+        resizingId = el.id;
+        resizeDir = dir;
+        startX = e.clientX;
+        startY = e.clientY;
+        initialW = el.width;
+        initialH = el.height;
+        e.stopPropagation();
    }

-    function handleMouseUp() {
-        if (draggingId && editable) {
-            onLayoutChange?.(elements);
+    function handleWindowMouseMove(e: MouseEvent) {
+        if (!editable) return;
+
+        if (draggingId) {
+            dragMoved = true;
+            const index = elements.findIndex(el => el.id === draggingId);
+            if (index !== -1) {
+                const dx = (e.clientX - startX) / GRID_SIZE;
+                const dy = (e.clientY - startY) / GRID_SIZE;
+                
+                let newX = initialX + dx;
+                let newY = initialY + dy;
+                
+                if (snapStep > 0) {
+                    newX = Math.round(newX / snapStep) * snapStep;
+                    newY = Math.round(newY / snapStep) * snapStep;
+                }
+
+                const currentEl = elements[index];
+                if (currentEl) {
+                    elements[index] = { ...currentEl, x: Math.max(0, newX), y: Math.max(0, newY) };
+                }
+            }
+        } else if (resizingId && resizeDir) {
+            const index = elements.findIndex(el => el.id === resizingId);
+            if (index !== -1) {
+                const dx = (e.clientX - startX) / GRID_SIZE;
+                const dy = (e.clientY - startY) / GRID_SIZE;
+                
+                let newW = initialW;
+                let newH = initialH;
+
+                if (resizeDir.includes('e')) newW = initialW + dx;
+                if (resizeDir.includes('s')) newH = initialH + dy;
+
+                if (snapStep > 0) {
+                    newW = Math.round(newW / snapStep) * snapStep;
+                    newH = Math.round(newH / snapStep) * snapStep;
+                }
+
+                const currentEl = elements[index];
+                if (currentEl) {
+                    elements[index] = { 
+                        ...currentEl, 
+                        width: Math.max(snapStep || 0.1, newW), 
+                        height: Math.max(snapStep || 0.1, newH) 
+                    };
+                }
+            }
+        }
+    }
+
+    function handleWindowMouseUp() {
+        if (editable) {
+            if (draggingId) {
+                if (dragMoved) {
+                    onLayoutChange?.(elements);
+                } else {
+                    const el = elements.find(e => e.id === draggingId);
+                    if (el) onElementClick?.(el);
+                }
+            } else if (resizingId) {
+                onLayoutChange?.(elements);
+            }
        }
        draggingId = null;
+        resizingId = null;
+        resizeDir = null;
+        dragMoved = false;
    }

-    const GRID_SIZE = 40;
+    // Compute viewBox based on elements or default
+    let maxX = $derived(elements.reduce((max, el) => Math.max(max, el.x + el.width), 20));
+    let maxY = $derived(elements.reduce((max, el) => Math.max(max, el.y + el.height), 15));
+    let viewBox = $derived(`0 0 ${Math.ceil(maxX * GRID_SIZE)} ${Math.ceil(maxY * GRID_SIZE)}`);
 </script>

+<svelte:window 
+    onmousemove={handleWindowMouseMove} 
+    onmouseup={handleWindowMouseUp} 
+/>
+
 <!-- svelte-ignore a11y_no_static_element_interactions -->
+<!-- svelte-ignore a11y_click_events_have_key_events -->
 <svg 
-    width="800" 
-    height="600" 
+    {viewBox}
+    preserveAspectRatio="xMidYMid meet"
    class="room-canvas" 
    class:editable
-    onmousemove={handleMouseMove}
-    onmouseup={handleMouseUp}
-    onmouseleave={handleMouseUp}
+    class:clickable={clickable || editable}
+    onclick={(e) => {
+        // Deselect if clicking on empty canvas
+        if (editable && e.target === e.currentTarget) {
+            onElementClick?.(null);
+        }
+    }}
 >
    <!-- Grid -->
-    {#if editable}
+    {#if editable && snapStep > 0}
        <defs>
-            <pattern id="grid" width={GRID_SIZE} height={GRID_SIZE} patternUnits="userSpaceOnUse">
-                <path d="M {GRID_SIZE} 0 L 0 0 0 {GRID_SIZE}" fill="none" stroke="#eee" stroke-width="1"/>
+            <pattern id="grid" width={GRID_SIZE * snapStep} height={GRID_SIZE * snapStep} patternUnits="userSpaceOnUse">
+                <path d="M {GRID_SIZE * snapStep} 0 L 0 0 0 {GRID_SIZE * snapStep}" fill="none" stroke="var(--rule-soft)" stroke-width="1" stroke-dasharray="2,2"/>
            </pattern>
        </defs>
        <rect width="100%" height="100%" fill="url(#grid)" />
@@ -93,7 +188,7 @@
                <rect 
                    width={el.width * GRID_SIZE} 
                    height={el.height * GRID_SIZE} 
-                    rx="4"
+                    rx="8"
                />
                <text 
                    x={(el.width * GRID_SIZE) / 2} 
@@ -106,7 +201,7 @@
                {#if studentNames[el.id]}
                    <text 
                        x={(el.width * GRID_SIZE) / 2} 
-                        y={(el.height * GRID_SIZE) + 15} 
+                        y={(el.height * GRID_SIZE) + 14} 
                        text-anchor="middle" 
                        class="student-name"
                    >
@@ -117,72 +212,124 @@
                <rect 
                    width={el.width * GRID_SIZE} 
                    height={el.height * GRID_SIZE} 
-                    fill="#e9ecef"
-                    stroke="#dee2e6"
+                    rx="16"
                />
+            {:else if el.type === 'gap'}
+                <!-- Invisible interaction target -->
+                <rect 
+                    width={el.width * GRID_SIZE} 
+                    height={el.height * GRID_SIZE} 
+                    fill="transparent"
+                    stroke={editable ? "var(--rule)" : "none"}
+                    stroke-dasharray="4,4"
+                />
+                {#if editable}
+                    <text 
+                        x={(el.width * GRID_SIZE) / 2} 
+                        y={(el.height * GRID_SIZE) / 2} 
+                        text-anchor="middle" 
+                        dominant-baseline="middle"
+                        style="font-size: 10px; fill: var(--ink-4);"
+                    >
+                        GAP
+                    </text>
+                {/if}
            {:else if el.type === 'door'}
                <rect 
                    width={el.width * GRID_SIZE} 
                    height={el.height * GRID_SIZE} 
-                    fill="#ffeeba"
-                    stroke="#ffe082"
+                    fill="transparent"
+                    stroke="var(--rule)"
+                    stroke-width="2"
                />
                <text 
                    x={(el.width * GRID_SIZE) / 2} 
                    y={(el.height * GRID_SIZE) / 2} 
                    text-anchor="middle" 
                    dominant-baseline="middle"
-                    style="font-size: 10px;"
+                    style="font-size: 10px; fill: var(--ink-3); font-family: var(--mono); letter-spacing: 0.1em;"
                >
                    DOOR
                </text>
            {/if}
+
+            {#if editable && selectedId === el.id}
+                <!-- Resize handles -->
+                <rect class="resize-handle e" x={el.width * GRID_SIZE - 4} y={(el.height * GRID_SIZE) / 2 - 4} width="8" height="8" onmousedown={(e) => handleResizeDown(e, el, 'e')} />
+                <rect class="resize-handle s" x={(el.width * GRID_SIZE) / 2 - 4} y={el.height * GRID_SIZE - 4} width="8" height="8" onmousedown={(e) => handleResizeDown(e, el, 's')} />
+                <rect class="resize-handle se" x={el.width * GRID_SIZE - 4} y={el.height * GRID_SIZE - 4} width="8" height="8" onmousedown={(e) => handleResizeDown(e, el, 'se')} />
+            {/if}
        </g>
    {/each}
 </svg>

 <style>
    .room-canvas {
-        background: white;
-        border: 1px solid #ccc;
+        background: transparent;
+        width: 100%;
+        height: auto;
        user-select: none;
+        touch-action: none;
    }
-    .room-canvas.editable {
-        cursor: crosshair;
-    }
-    .element {
+    .room-canvas.clickable .element {
        cursor: pointer;
    }
+    
+    .element rect {
+        transition: fill 0.2s, stroke 0.2s;
+    }
+
    .element.seat rect {
-        fill: #fff;
-        stroke: #007bff;
-        stroke-width: 2;
+        fill: #fbf7ee;
+        stroke: var(--ink-2);
+        stroke-width: 1.5;
    }
    .element.seat text {
-        fill: #007bff;
-        font-weight: bold;
-        font-size: 14px;
+        fill: var(--ink);
+        font-weight: 500;
+        font-family: var(--mono);
+        font-size: 12px;
    }
+    
    .element.seat.occupied rect {
-        fill: #e7f1ff;
-        stroke: #6c757d;
+        fill: #d6cdb5;
+        stroke: var(--ink-2);
    }
    .element.seat.occupied text {
-        fill: #6c757d;
+        fill: var(--ink-2);
    }
+
    .element.seat.is-mine rect {
-        fill: #28a745;
-        stroke: #1e7e34;
+        fill: var(--accent);
+        stroke: var(--accent);
    }
    .element.seat.is-mine text {
        fill: white;
    }
+
    .element.selected rect {
-        stroke: #ffc107;
-        stroke-width: 3;
+        stroke: var(--highlight);
+        stroke-width: 2.5;
    }
+    
+    .element.table rect {
+        fill: rgba(0,0,0,0.03);
+        stroke: var(--rule);
+        stroke-width: 1;
+    }
+
    .student-name {
-        font-size: 10px;
-        fill: #333;
+        font-size: 11px;
+        fill: var(--ink-3);
+        font-family: var(--sans);
    }
+
+    .resize-handle {
+        fill: white;
+        stroke: var(--accent);
+        stroke-width: 1.5;
+    }
+    .resize-handle.e { cursor: ew-resize; }
+    .resize-handle.s { cursor: ns-resize; }
+    .resize-handle.se { cursor: nwse-resize; }
 </style>
--- a/frontend/src/lib/api.ts
+++ b/frontend/src/lib/api.ts
@@ -44,7 +44,10 @@ export async function request<T>(path: string, init?: RequestInit): Promise<T> {
    }

    if (res.status === 204) return {} as T;
-    return res.json() as Promise<T>;
+
+    const text = await res.text();
+    if (!text) return {} as T;
+    return JSON.parse(text) as T;
 }

 export const api = {
@@ -96,6 +99,11 @@ export const api = {
                    body: JSON.stringify(tutor) 
                }),
            delete: (id: number) => request<void>(`/admin/tutors/${id}`, { method: 'DELETE' }),
+            setActive: (id: number, is_active: boolean) => 
+                request<void>(`/admin/tutors/${id}/active`, { 
+                    method: 'PATCH', 
+                    body: JSON.stringify({ is_active }) 
+                }),
        },
        students: {
            delete: (id: number) => request<void>(`/admin/students/${id}`, { method: 'DELETE' }),
@@ -115,6 +123,7 @@ export const api = {
                    method: 'PUT', 
                    body: JSON.stringify(layout) 
                }),
+            delete: (id: number) => request<void>(`/admin/rooms/${id}`, { method: 'DELETE' }),
        },
        sessions: {
            list: (course_id: number) => request<Session[]>(`/admin/sessions?course_id=${course_id}`),
@@ -163,7 +172,7 @@ export const api = {
        getInfo: (code: string) => request<CheckinInfo>(`/checkin/${code}`),
        getStudents: (code: string) => request<Student[]>(`/checkin/${code}/students`),
        post: (code: string, student_id: number, seat_id?: string) =>
-            request<Attendance>('/checkin', {
+            request<{ok: boolean}>('/checkin', {
                method: 'POST', 
                body: JSON.stringify({ code, student_id, seat_id }) 
            }),
--- a/frontend/src/lib/components/SeatMap.svelte
+++ b/frontend/src/lib/components/SeatMap.svelte
@@ -1,169 +0,0 @@
-<script lang="ts">
-  interface SeatDef {
-    id: string;
-    x: number;
-    y: number;
-    table: string;
-  }
-
-  interface StudentRef {
-    id: number;
-    name: string;
-    initials: string;
-  }
-
-  const {
-    assignments = {},
-    students = [],
-    selectedStudent = null,
-    onSeatClick,
-    variant = 'tutor',
-    ownSeat = null,
-    scale = 1,
-  } = $props<{
-    assignments?: Record<string, number>;
-    students?: StudentRef[];
-    selectedStudent?: number | null;
-    onSeatClick?: (seat: SeatDef) => void;
-    variant?: 'tutor' | 'student' | 'student-self';
-    ownSeat?: string | null;
-    scale?: number;
-  }>();
-
-  const W = 760;
-  const H = 460;
-
-  const WALLS  = { x: 12,  y: 12,  w: 736, h: 436 };
-  const WINDOW = { x: 12,  y: 120, w: 6,   h: 220 };
-  const DOOR   = { x: 60,  y: 448, w: 70,  h: 6   };
-  const BEAMER = { x: 372, y: 24,  w: 110, h: 8   };
-  const PODIUM = { x: 332, y: 60,  w: 190, h: 38  };
-  const TABLES = [
-    { id: 'T1', x: 90,  y: 150, w: 200, h: 70, label: 'T1' },
-    { id: 'T2', x: 470, y: 150, w: 200, h: 70, label: 'T2' },
-    { id: 'T3', x: 90,  y: 320, w: 200, h: 70, label: 'T3' },
-    { id: 'T4', x: 470, y: 320, w: 200, h: 70, label: 'T4' },
-  ];
-
-  function makeSeats(): SeatDef[] {
-    return TABLES.flatMap((t) => [
-      { id: `${t.id}-1`, x: t.x + t.w * 0.28, y: t.y - 22,        table: t.id },
-      { id: `${t.id}-2`, x: t.x + t.w * 0.72, y: t.y - 22,        table: t.id },
-      { id: `${t.id}-3`, x: t.x + t.w * 0.28, y: t.y + t.h + 22,  table: t.id },
-      { id: `${t.id}-4`, x: t.x + t.w * 0.72, y: t.y + t.h + 22,  table: t.id },
-      { id: `${t.id}-5`, x: t.x + t.w + 26,   y: t.y + t.h / 2,   table: t.id },
-    ]);
-  }
-
-  const SEATS = makeSeats();
-
-  function studentById(id: number): StudentRef | undefined {
-    return students.find((s: StudentRef) => s.id === id);
-  }
-
-  function seatStyle(seat: SeatDef): { bg: string; border: string; label: string; labelColor: string; shadow: string } {
-    const sid = assignments[seat.id];
-    const student = sid ? studentById(sid) : undefined;
-    const isSelected = selectedStudent != null && sid === selectedStudent;
-    const isOwn = ownSeat === seat.id;
-
-    if (variant === 'tutor') {
-      if (student) {
-        return {
-          bg: isSelected ? 'var(--ink)' : '#fbf7ee',
-          border: isSelected ? 'var(--ink)' : 'var(--ink-2)',
-          label: student.initials,
-          labelColor: isSelected ? '#f7eedc' : 'var(--ink)',
-          shadow: isSelected ? '0 0 0 3px rgba(241,211,106,0.6)' : 'none',
-        };
-      }
-      return { bg: '#f7f1e3', border: 'var(--ink-4)', label: '', labelColor: 'var(--ink-4)', shadow: 'none' };
-    }
-
-    if (variant === 'student') {
-      if (isOwn) {
-        return { bg: 'var(--accent)', border: 'var(--accent)', label: '★', labelColor: '#f7eedc', shadow: 'none' };
-      }
-      if (sid) {
-        return { bg: '#d6cdb5', border: 'var(--ink-4)', label: '', labelColor: '', shadow: 'none' };
-      }
-      return { bg: '#fbf7ee', border: 'var(--ink-2)', label: '', labelColor: '', shadow: 'none' };
-    }
-
-    // student-self (read-only)
-    if (isOwn) {
-      return { bg: 'var(--accent)', border: 'var(--accent)', label: '★', labelColor: '#f7eedc', shadow: 'none' };
-    }
-    if (sid) {
-      return { bg: '#d6cdb5', border: 'var(--ink-4)', label: '', labelColor: '', shadow: 'none' };
-    }
-    return { bg: '#fbf7ee', border: 'var(--ink-3)', label: '', labelColor: '', shadow: 'none' };
-  }
-</script>
-
-<div style="position:relative;width:{W * scale}px;height:{H * scale}px;background:#f7f1e3;border:1px solid var(--rule);border-radius:4px;overflow:hidden;box-shadow:inset 0 0 0 1px rgba(0,0,0,0.02),0 1px 0 rgba(0,0,0,0.03)">
-
-  <!-- Inner graph-paper grid -->
-  <div style="position:absolute;inset:0;background-image:linear-gradient(to right,rgba(110,90,60,0.05) 1px,transparent 1px),linear-gradient(to bottom,rgba(110,90,60,0.05) 1px,transparent 1px);background-size:{24*scale}px {24*scale}px"></div>
-
-  <!-- Design-space inner container at 1× coords, CSS-scaled -->
-  <div style="position:absolute;inset:0;transform:scale({scale});transform-origin:top left;width:{W}px;height:{H}px">
-
-    <!-- Walls -->
-    <div style="position:absolute;left:{WALLS.x}px;top:{WALLS.y}px;width:{WALLS.w}px;height:{WALLS.h}px;border:2px solid var(--ink-2);border-radius:2px"></div>
-
-    <!-- Window -->
-    <div style="position:absolute;left:{WINDOW.x - 2}px;top:{WINDOW.y}px;width:{WINDOW.w + 4}px;height:{WINDOW.h}px;background:#dfeaf0;border-top:2px solid var(--ink-2);border-bottom:2px solid var(--ink-2)">
-      <div style="position:absolute;left:1px;top:50%;width:{WINDOW.w + 2}px;height:2px;background:var(--ink-2)"></div>
-    </div>
-    <div style="position:absolute;left:-8px;top:{WINDOW.y + WINDOW.h / 2 - 6}px;font-family:var(--mono);font-size:9px;color:var(--ink-3);transform:rotate(-90deg);transform-origin:left top;letter-spacing:0.1em;text-transform:uppercase">Fenster</div>
-
-    <!-- Door gap + arc -->
-    <div style="position:absolute;left:{DOOR.x}px;top:{DOOR.y - 2}px;width:{DOOR.w}px;height:4px;background:#f7f1e3"></div>
-    <svg style="position:absolute;left:{DOOR.x}px;top:{DOOR.y - 36}px;pointer-events:none" width="{DOOR.w + 10}" height="40">
-      <path d="M 2 38 Q 2 2 {DOOR.w} 2" stroke="var(--ink-3)" stroke-width="1" stroke-dasharray="2 2" fill="none"/>
-      <line x1="2" y1="38" x2="2" y2="2" stroke="var(--ink-2)" stroke-width="1.5"/>
-    </svg>
-    <div style="position:absolute;left:{DOOR.x + 6}px;top:{DOOR.y + 6}px;font-family:var(--mono);font-size:9px;color:var(--ink-3);letter-spacing:0.1em;text-transform:uppercase">Tür</div>
-
-    <!-- Beamer -->
-    <div style="position:absolute;left:{BEAMER.x}px;top:{BEAMER.y}px;width:{BEAMER.w}px;height:{BEAMER.h}px;background:var(--ink-2);border-radius:1px"></div>
-    <div style="position:absolute;left:{BEAMER.x + BEAMER.w + 6}px;top:{BEAMER.y}px;font-family:var(--mono);font-size:9px;color:var(--ink-3);letter-spacing:0.1em;text-transform:uppercase">Beamer</div>
-
-    <!-- Podium -->
-    <div style="position:absolute;left:{PODIUM.x}px;top:{PODIUM.y}px;width:{PODIUM.w}px;height:{PODIUM.h}px;border:1.5px solid var(--ink-2);background:#efe6d2;border-radius:2px;display:flex;align-items:center;justify-content:center;font-family:var(--mono);font-size:10px;color:var(--ink-3);letter-spacing:0.15em;text-transform:uppercase">
-      Pult · Tutor:in
-    </div>
-
-    <!-- Tables -->
-    {#each TABLES as t (t.id)}
-      <div style="position:absolute;left:{t.x}px;top:{t.y}px;width:{t.w}px;height:{t.h}px;background:#e8dec5;border:1.5px solid var(--ink-2);border-radius:3px;display:flex;align-items:center;justify-content:center;font-family:var(--serif);font-size:22px;color:rgba(31,27,22,0.35);font-style:italic">
-        {t.label}
-      </div>
-    {/each}
-
-    <!-- Seats -->
-    {#each SEATS as seat (seat.id)}
-      {@const s = seatStyle(seat)}
-      <button
-        style="position:absolute;left:{seat.x - 18}px;top:{seat.y - 18}px;width:36px;height:36px;border-radius:50%;background:{s.bg};border:1.5px solid {s.border};cursor:{onSeatClick && variant !== 'student-self' ? 'pointer' : 'default'};display:flex;align-items:center;justify-content:center;font-family:var(--sans);font-weight:600;font-size:11px;color:{s.labelColor};padding:0;box-shadow:{s.shadow};transition:background 120ms,border-color 120ms"
-        title={assignments[seat.id] ? (studentById(assignments[seat.id])?.name ?? 'besetzt') : 'frei'}
-        disabled={variant === 'student-self'}
-        onclick={() => onSeatClick?.(seat)}
-      >
-        {s.label}
-      </button>
-    {/each}
-
-    <!-- Compass -->
-    <div style="position:absolute;right:18px;bottom:14px;font-family:var(--mono);font-size:9px;color:var(--ink-3);letter-spacing:0.15em">
-      <div style="display:flex;flex-direction:column;align-items:center">
-        <span>N</span>
-        <svg width="14" height="22">
-          <path d="M7 2 L7 20 M3 6 L7 2 L11 6" stroke="var(--ink-3)" stroke-width="1" fill="none"/>
-        </svg>
-      </div>
-    </div>
-
-  </div>
-</div>
--- a/frontend/src/lib/components/TutorShell.svelte
+++ b/frontend/src/lib/components/TutorShell.svelte
@@ -1,6 +1,8 @@
 <script lang="ts">
  import type { Snippet } from 'svelte';
  import { auth } from '$lib/auth.svelte';
+  import { api } from '$lib/api';
+  import { goto } from '$app/navigation';

  const {
    activePath,
@@ -40,6 +42,16 @@
  function initials(name: string): string {
    return name.split(' ').map((w) => w[0]).slice(0, 2).join('').toUpperCase();
  }
+
+  async function handleLogout() {
+    try {
+      await api.auth.logout();
+    } catch (e) {
+      console.error('Logout failed', e);
+    }
+    auth.logout();
+    goto('/admin/login');
+  }
 </script>

 <div class="paper-bg" style="width:100%;min-height:100vh;display:grid;grid-template-columns:220px 1fr;overflow:hidden">
@@ -79,6 +91,14 @@
          </a>
        {/if}
      {/each}
+
+      <button
+        onclick={handleLogout}
+        style="text-align:left;text-decoration:none;background:transparent;padding:8px 10px;border-radius:4px;font-family:var(--sans);font-size:13px;color:var(--ink-2);border:none;cursor:pointer;display:flex;align-items:center;gap:8px;margin-top:12px;border-top:1px solid var(--rule);width:100%"
+      >
+        <span style="width:4px;height:4px;border-radius:50%;flex-shrink:0;background:var(--ink-4)"></span>
+        Abmelden
+      </button>
    </nav>

    <div style="flex:1"></div>
--- a/frontend/src/lib/types.ts
+++ b/frontend/src/lib/types.ts
@@ -9,6 +9,7 @@ export interface Tutor {
    name: string;
    email: string;
    is_superadmin: boolean;
+    is_active: boolean;
 }

 export interface Student {
@@ -50,6 +51,7 @@ export interface Slot {
    end_time: string;
    status: "closed" | "open" | "locked";
    code: string | null;
+    layout?: LayoutElement[];
 }

 export interface Attendance {
--- a/frontend/src/routes/admin/live/[slotId]/+page.svelte
+++ b/frontend/src/routes/admin/live/[slotId]/+page.svelte
@@ -6,7 +6,7 @@
  import Icon from '$lib/components/Icon.svelte';
  import StatusPill from '$lib/components/StatusPill.svelte';
  import NoteEditor from '$lib/components/NoteEditor.svelte';
-  import SeatMap from '$lib/components/SeatMap.svelte';
+  import RoomCanvas from '$lib/RoomCanvas.svelte';
  import UnderlineStroke from '$lib/components/UnderlineStroke.svelte';
  import Tally from '$lib/components/Tally.svelte';

@@ -22,6 +22,7 @@
  let loading = $state(true);

  let pollInterval: ReturnType<typeof setInterval> | null = null;
+  let loadError = $state<string | null>(null);

  onMount(async () => {
    await loadData();
@@ -59,6 +60,11 @@
            session = sess;
            students = await api.admin.courses.listStudents(course.id);
            const attendance = await api.admin.sessions.getAttendance(sess.id);
+            // Instead of just taking the session layout, the slot comes with its own layout from get_session_attendance now
+            const fullSlot = attendance.slots.find(s => s.id === slotId);
+            if (fullSlot) {
+                slot = fullSlot;
+            }
            attendances = (attendance.attendances ?? []).filter((a: Attendance) => a.slot_id === slotId);
            notes = await api.admin.slots.getNotes(slotId);
            found = true;
@@ -68,7 +74,8 @@
        if (found) break;
      }
    } catch (e) {
-      console.error(e);
+      loadError = e instanceof Error ? e.message : 'Daten konnten nicht geladen werden.';
+      console.error('[live/loadData]', e);
    }
  }

@@ -101,6 +108,29 @@

  const presentCount = $derived(attendances.length);
  const absentCount = $derived(students.length - presentCount);
+  
+  const occupiedSeatIds = $derived(attendances.map(a => a.seat_id).filter(Boolean) as string[]);
+  const studentNamesBySeat = $derived((() => {
+      const map: Record<string, string> = {};
+      for (const att of attendances) {
+          if (att.seat_id) {
+              const student = students.find(s => s.id === att.student_id);
+              if (student) {
+                  map[att.seat_id] = student.name;
+              }
+          }
+      }
+      return map;
+  })());
+
+  function handleSeatClick(el: { id: string } | null) {
+      if (!el) {
+          selectedStudentId = null;
+          return;
+      }
+      const att = attendances.find(a => a.seat_id === el.id);
+      selectedStudentId = att ? att.student_id : null;
+  }

  function weekLabel(n: number): string {
    return `W${String(n).padStart(2, '0')}`;
@@ -109,6 +139,12 @@

 <div style="padding:28px 36px;display:flex;flex-direction:column;gap:22px">

+  {#if loadError}
+    <div style="background:rgba(138,44,31,0.06);border:1px solid var(--accent);color:var(--accent);padding:10px 14px;border-radius:4px;font-size:13px">
+      Fehler beim Laden: {loadError}
+    </div>
+  {/if}
+
  {#if loading}
    <div style="padding:48px;text-align:center">
      <span class="small" style="color:var(--ink-4)">Wird geladen…</span>
@@ -158,7 +194,13 @@
        </div>

        <div class="card" style="overflow:hidden;padding:16px">
-          <SeatMap variant="tutor" scale={0.78} />
+          <RoomCanvas 
+            elements={slot.layout ?? []} 
+            clickable={true} 
+            occupiedSeatIds={occupiedSeatIds} 
+            studentNames={studentNamesBySeat}
+            onElementClick={handleSeatClick} 
+          />
        </div>

        <!-- Tally row -->
--- a/frontend/src/routes/admin/rooms/+page.svelte
+++ b/frontend/src/routes/admin/rooms/+page.svelte
@@ -5,19 +5,42 @@

  let rooms = $state<Room[]>([]);
  let newRoomName = $state('');
+  let errorMsg = $state<string | null>(null);

  onMount(async () => {
-    rooms = await api.admin.rooms.list();
+    try {
+      rooms = await api.admin.rooms.list();
+    } catch (e) {
+      errorMsg = e instanceof Error ? e.message : 'Räume konnten nicht geladen werden.';
+    }
  });

  async function createRoom() {
    if (!newRoomName.trim()) return;
+    errorMsg = null;
    try {
      await api.admin.rooms.create(newRoomName, []);
      newRoomName = '';
+    } catch (e) {
+      errorMsg = e instanceof Error ? e.message : 'Raum konnte nicht erstellt werden.';
+      console.error('[rooms/createRoom]', e);
+      return;
+    }
+    try {
      rooms = await api.admin.rooms.list();
-    } catch {
-      console.error('failed to fetch rooms');
+    } catch (e) {
+      console.error('[rooms/createRoom/list]', e);
+    }
+  }
+
+  async function deleteRoom(id: number) {
+    if (!confirm('Raum wirklich löschen?')) return;
+    errorMsg = null;
+    try {
+      await api.admin.rooms.delete(id);
+      rooms = await api.admin.rooms.list();
+    } catch (err) {
+      errorMsg = err instanceof Error ? err.message : 'Raum konnte nicht gelöscht werden.';
    }
  }
 </script>
@@ -28,6 +51,12 @@
    <h1 class="h1" style="font-family:var(--serif)">Raumlayout-Editor</h1>
  </div>

+  {#if errorMsg}
+    <div style="background:rgba(138,44,31,0.06);border:1px solid var(--accent);color:var(--accent);padding:10px 14px;border-radius:4px;font-size:13px;margin-bottom:12px">
+      {errorMsg}
+    </div>
+  {/if}
+
  <div class="card" style="overflow:hidden">
    <div style="padding:14px 18px;border-bottom:1px solid var(--rule);display:flex;align-items:center;justify-content:space-between">
      <div class="serif" style="font-size:18px;font-weight:500">Räume</div>
@@ -54,7 +83,10 @@
            <tr class="row-hover" style="border-top:{i === 0 ? 'none' : '1px solid var(--rule)'}">
              <td style="padding:12px 14px">{room.name}</td>
              <td style="padding:12px 14px;text-align:right">
-                <a href="/admin/rooms/{room.id}" class="btn ghost sm">Bearbeiten</a>
+                <div style="display:flex;justify-content:flex-end;gap:8px">
+                    <a href="/admin/rooms/{room.id}" class="btn ghost sm">Bearbeiten</a>
+                    <button class="btn ghost sm" style="color:var(--accent);border-color:rgba(138,44,31,0.2)" onclick={() => deleteRoom(room.id)}>Löschen</button>
+                </div>
              </td>
            </tr>
          {/each}
--- a/frontend/src/routes/admin/rooms/[roomId]/+page.svelte
+++ b/frontend/src/routes/admin/rooms/[roomId]/+page.svelte
@@ -1,6 +1,5 @@
 <script lang="ts">
  import { page } from '$app/stores';
-  import { onMount } from 'svelte';
  import { api } from '$lib/api';
  import RoomCanvas from '$lib/RoomCanvas.svelte';
  import type { Room, LayoutElement } from '$lib/types';
@@ -9,38 +8,82 @@
  const roomId = $derived(roomIdStr ? parseInt(roomIdStr) : 0);

  let room = $state<Room | null>(null);
-
-  onMount(async () => {
-    room = await api.admin.rooms.get(roomId);
-  });
+  let errorMsg = $state<string | null>(null);
+  let snapToGrid = $state(true);

  $effect(() => {
    if (roomId) {
-      api.admin.rooms.get(roomId).then((r: Room) => { room = r; });
+      api.admin.rooms.get(roomId)
+        .then((r: Room) => { room = r; })
+        .catch((e: unknown) => {
+          errorMsg = e instanceof Error ? e.message : 'Raum konnte nicht geladen werden.';
+        });
    }
  });

  async function saveLayout() {
    if (!room) return;
+    errorMsg = null;
    try {
      await api.admin.rooms.updateLayout(room.id, room.layout);
-    } catch {
-        console.error('failed to save layout');
+    } catch (e) {
+      errorMsg = e instanceof Error ? e.message : 'failed to save layout';
    }
  }

  function addElement(type: LayoutElement['type']) {
    if (!room) return;
-    const id = Math.random().toString(36).substr(2, 9);
+    const id = Math.random().toString(36).slice(2, 11);
+    let nextLabel: string;
+    
+    if (type === 'seat') {
+      const existingLabels = room.layout
+        .filter((e: LayoutElement) => e.type === 'seat')
+        .map((e: LayoutElement) => parseInt(e.label, 10))
+        .filter(n => !isNaN(n));
+      const maxLabel = existingLabels.length > 0 ? Math.max(...existingLabels) : 0;
+      nextLabel = (maxLabel + 1).toString();
+    } else {
+      nextLabel = '';
+    }
+
    const newEl: LayoutElement = {
      id,
-      label: type === 'seat' ? (room.layout.filter((e: LayoutElement) => e.type === 'seat').length + 1).toString() : '',
+      label: nextLabel,
      x: 0, y: 0,
      width: type === 'table' ? 2 : 1,
      height: 1,
      type,
    };
    room.layout = [...room.layout, newEl];
+    selectedElementId = id;
+  }
+
+  function duplicateElement() {
+    if (!room || !selectedElement) return;
+    const id = Math.random().toString(36).slice(2, 11);
+    
+    let nextLabel: string;
+    if (selectedElement.type === 'seat') {
+      const existingLabels = room.layout
+        .filter((e: LayoutElement) => e.type === 'seat')
+        .map((e: LayoutElement) => parseInt(e.label, 10))
+        .filter(n => !isNaN(n));
+      const maxLabel = existingLabels.length > 0 ? Math.max(...existingLabels) : 0;
+      nextLabel = (maxLabel + 1).toString();
+    } else {
+        nextLabel = selectedElement.label;
+    }
+
+    const duplicatedEl: LayoutElement = {
+        ...selectedElement,
+        id,
+        label: nextLabel,
+        x: selectedElement.x + (snapToGrid ? 0.5 : 0.1),
+        y: selectedElement.y + (snapToGrid ? 0.5 : 0.1),
+    };
+    room.layout = [...room.layout, duplicatedEl];
+    selectedElementId = id;
  }

  let selectedElementId = $state<string | null>(null);
@@ -61,20 +104,31 @@
        <h2 class="h2" style="font-family:var(--serif)">{room.name}</h2>
      </div>
      <div style="display:flex;gap:8px">
+        <label style="display:flex;align-items:center;gap:6px;cursor:pointer;margin-right:12px;font-size:13px;color:var(--ink-3)">
+            <input type="checkbox" bind:checked={snapToGrid} /> Raster fangen
+        </label>
        <button class="btn ghost" onclick={() => addElement('seat')}>+ Sitz</button>
        <button class="btn ghost" onclick={() => addElement('table')}>+ Tisch</button>
        <button class="btn ghost" onclick={() => addElement('door')}>+ Tür</button>
+        <button class="btn ghost" onclick={() => addElement('gap')}>+ Gap</button>
        <button class="btn" onclick={saveLayout}>Speichern</button>
      </div>
    </div>
+    
+    {#if errorMsg}
+      <div style="background:rgba(138,44,31,0.06);border:1px solid var(--accent);color:var(--accent);padding:10px 14px;border-radius:4px;font-size:13px">
+          {errorMsg}
+      </div>
+    {/if}

    <div style="display:flex;gap:20px">
      <div style="flex:1">
        <RoomCanvas
          bind:elements={room.layout}
          editable={true}
+          snapStep={snapToGrid ? 0.5 : 0}
          selectedId={selectedElementId}
-          onElementClick={(el) => { selectedElementId = el.id; }}
+          onElementClick={(el) => { selectedElementId = el ? el.id : null; }}
        />
      </div>

@@ -86,6 +140,16 @@
              <div class="tiny" style="color:var(--ink-3)">Bezeichnung</div>
              <input class="input" bind:value={selectedElement.label} />
            </div>
+            <div style="display:grid;grid-template-columns:1fr 1fr;gap:8px">
+              <div>
+                <div class="tiny" style="color:var(--ink-3)">X-Pos</div>
+                <input class="input" type="number" step="0.5" bind:value={selectedElement.x} />
+              </div>
+              <div>
+                <div class="tiny" style="color:var(--ink-3)">Y-Pos</div>
+                <input class="input" type="number" step="0.5" bind:value={selectedElement.y} />
+              </div>
+            </div>
            <div style="display:grid;grid-template-columns:1fr 1fr;gap:8px">
              <div>
                <div class="tiny" style="color:var(--ink-3)">Breite</div>
@@ -96,6 +160,11 @@
                <input class="input" type="number" step="0.5" bind:value={selectedElement.height} />
              </div>
            </div>
+            <div style="height:1px;background:var(--rule);margin:8px 0"></div>
+            <button
+              class="btn ghost sm" style="justify-content:center"
+              onclick={duplicateElement}
+            >Duplizieren</button>
            <button
              style="color:var(--accent);background:none;border:none;cursor:pointer;text-align:left;font-family:var(--sans);font-size:13px;padding:4px 0"
              onclick={deleteElement}
--- a/frontend/src/routes/admin/tutors/+page.svelte
+++ b/frontend/src/routes/admin/tutors/+page.svelte
@@ -7,6 +7,7 @@

  let tutors = $state<Tutor[]>([]);
  let loading = $state(true);
+  let loadError = $state<string | null>(null);

  let newTutor = $state({
    name: '',
@@ -23,8 +24,10 @@
  async function loadTutors() {
    try {
      tutors = await api.admin.tutors.list();
+      loadError = null;
    } catch (e) {
-      console.error(e);
+      loadError = e instanceof Error ? e.message : 'Tutor:innen konnten nicht geladen werden.';
+      console.error('[tutors/loadTutors]', e);
    }
  }

@@ -49,6 +52,15 @@
    }
  }

+  async function toggleActive(tutor: Tutor) {
+    try {
+      await api.admin.tutors.setActive(tutor.id, !tutor.is_active);
+      await loadTutors();
+    } catch (err) {
+      if (err instanceof Error) alert(err.message);
+    }
+  }
+
  function initials(name: string): string {
    return name.split(' ').map((w) => w[0]).slice(0, 2).join('').toUpperCase();
  }
@@ -75,12 +87,18 @@
        <UnderlineStroke width={120} />
      </div>

+      {#if loadError}
+        <div style="background:rgba(138,44,31,0.06);border:1px solid var(--accent);color:var(--accent);padding:10px 14px;border-radius:4px;font-size:13px;margin-bottom:12px">
+          {loadError}
+        </div>
+      {/if}
+
      <div class="card" style="overflow:hidden">
        {#if loading}
          <div style="padding:32px;text-align:center">
            <span class="small" style="color:var(--ink-4)">Wird geladen…</span>
          </div>
-        {:else if tutors.length === 0}
+        {:else if tutors.length === 0 && !loadError}
          <div style="padding:32px;text-align:center">
            <span class="small" style="color:var(--ink-4)">Keine Tutor:innen gefunden.</span>
          </div>
@@ -108,18 +126,31 @@
                    </div>
                  </td>
                  <td style="padding:12px 14px">
-                    {#if tutor.is_superadmin}
-                      <span class="pill locked">Superadmin</span>
-                    {:else}
-                      <span class="pill closed">Tutor:in</span>
-                    {/if}
+                    <div style="display:flex;flex-direction:column;gap:4px;align-items:flex-start">
+                      {#if tutor.is_superadmin}
+                        <span class="pill locked">Superadmin</span>
+                      {:else}
+                        <span class="pill closed">Tutor:in</span>
+                      {/if}
+                      {#if !tutor.is_active}
+                        <span class="pill inactive">Inaktiv</span>
+                      {/if}
+                    </div>
                  </td>
                  <td style="padding:12px 14px;text-align:right">
-                    <button
-                      class="btn ghost sm"
-                      style="color:var(--accent);border-color:rgba(138,44,31,0.2)"
-                      onclick={() => deleteTutor(tutor.id)}
-                    >Löschen</button>
+                    <div style="display:flex;justify-content:flex-end;gap:8px">
+                      <button
+                        class="btn ghost sm"
+                        onclick={() => toggleActive(tutor)}
+                      >
+                        {tutor.is_active ? 'Deaktivieren' : 'Aktivieren'}
+                      </button>
+                      <button
+                        class="btn ghost sm"
+                        style="color:var(--accent);border-color:rgba(138,44,31,0.2)"
+                        onclick={() => deleteTutor(tutor.id)}
+                      >Löschen</button>
+                    </div>
                  </td>
                </tr>
              {/each}
--- a/frontend/src/routes/s/[code]/+page.svelte
+++ b/frontend/src/routes/s/[code]/+page.svelte
@@ -2,8 +2,8 @@
  import { onMount } from 'svelte';
  import { page } from '$app/stores';
  import { api } from '$lib/api';
-  import type { Slot, Student, Attendance, CheckinAttendance } from '$lib/types';
-  import SeatMap from '$lib/components/SeatMap.svelte';
+  import type { Slot, Student, Attendance, CheckinAttendance, LayoutElement } from '$lib/types';
+  import RoomCanvas from '$lib/RoomCanvas.svelte';
  import StatusPill from '$lib/components/StatusPill.svelte';

  const code = $page.params.code as string;
@@ -13,6 +13,7 @@
  let errorMsg = $state('');

  let slot = $state<Slot | null>(null);
+  let layout = $state<LayoutElement[]>([]);
  let students = $state<Student[]>([]);
  let attendances = $state<CheckinAttendance[]>([]);
  let myAttendance = $state<Attendance | null>(null);
@@ -42,8 +43,10 @@
  async function loadInfo() {
    const res = await api.checkin.getInfo(code);
    slot = res.slot;
+    layout = res.layout ?? [];
    // We don't have is_mine in the regular Attendance type, so we use CheckinAttendance locally
    const checkinAttendances = res.attendances ?? [];
+    attendances = checkinAttendances;

    const mine = checkinAttendances.find((a: CheckinAttendance) => a.is_mine);
    if (mine && slot) {
@@ -77,20 +80,24 @@

  async function checkin(seatId?: string) {
    if (!selectedStudent) return;
+    errorMsg = '';
    try {
-      const res = await api.checkin.post(code, selectedStudent.id, seatId);
-      myAttendance = res;
-      await loadInfo();
+      await api.checkin.post(code, selectedStudent.id, seatId);
    } catch (e) {
      if (e instanceof Error) {
-          if (e.message?.includes('already checked in') || e.message?.includes('409')) {
-            errorMsg = 'Dieser Platz ist bereits belegt.';
-          } else {
-            errorMsg = e.message ?? 'Einchecken fehlgeschlagen.';
-          }
+        errorMsg = e.message.includes('seat taken')
+          ? 'Dieser Platz ist bereits belegt.'
+          : (e.message || 'Einchecken fehlgeschlagen.');
      } else {
-          errorMsg = 'Einchecken fehlgeschlagen.';
+        errorMsg = 'Einchecken fehlgeschlagen.';
      }
+      return;
+    }
+    try {
+      await loadInfo();
+    } catch (e) {
+      step = 'confirmed';
+      console.error('[checkin/loadInfo]', e);
    }
  }

@@ -102,6 +109,8 @@
    students.filter((s: Student) => s.name.toLowerCase().includes(search.toLowerCase()))
  );

+  const occupiedSeatIds = $derived(attendances.map(a => a.seat_id).filter(Boolean) as string[]);
+
  function initials(name: string): string {
    return name.split(' ').map((w: string) => w[0]).slice(0, 2).join('').toUpperCase();
  }
@@ -207,10 +216,11 @@
        {/if}

        <div style="overflow-x:auto">
-          <SeatMap
-            variant="student"
-            scale={0.46}
-            onSeatClick={(seat) => checkin(seat.id)}
+          <RoomCanvas
+            elements={layout}
+            clickable={true}
+            occupiedSeatIds={occupiedSeatIds}
+            onElementClick={(el) => { if (el?.type === 'seat' && !occupiedSeatIds.includes(el.id)) checkin(el.id); }}
          />
        </div>

@@ -245,7 +255,11 @@
        </div>

        <div style="overflow-x:auto">
-          <SeatMap variant="student-self" scale={0.46} ownSeat={myAttendance?.seat_id ?? null} />
+          <RoomCanvas
+            elements={layout}
+            mySeatId={myAttendance?.seat_id ?? null}
+            occupiedSeatIds={occupiedSeatIds}
+          />
        </div>

        <button class="btn ghost sm" style="align-self:center" onclick={changeSeat}>
@@ -313,10 +327,11 @@
            </div>
          {/if}

-          <SeatMap
-            variant="student"
-            scale={0.78}
-            onSeatClick={(seat) => checkin(seat.id)}
+          <RoomCanvas
+            elements={layout}
+            clickable={true}
+            occupiedSeatIds={occupiedSeatIds}
+            onElementClick={(el) => { if (el?.type === 'seat' && !occupiedSeatIds.includes(el.id)) checkin(el.id); }}
          />

          <div style="display:flex;gap:20px" class="tiny">
@@ -365,7 +380,11 @@
            </div>
          </div>

-          <SeatMap variant="student-self" scale={0.78} ownSeat={myAttendance?.seat_id ?? null} />
+          <RoomCanvas
+            elements={layout}
+            mySeatId={myAttendance?.seat_id ?? null}
+            occupiedSeatIds={occupiedSeatIds}
+          />

          <div style="display:flex;gap:10px">
            <button class="btn ghost" onclick={changeSeat}>Sitz wechseln</button>
--- a/scripts/test-env.sh
+++ b/scripts/test-env.sh
@@ -13,6 +13,15 @@ if [ "${TT_TEST_PORT_RANDOM:-0}" = "1" ]; then
  TT_TEST_PORT=0
 fi

+# If port is 0 and the backend already wrote its actual port, use it
+_port_file="${TT_WORKTREE_ROOT}/data/test/.port"
+if [ "$TT_TEST_PORT" = "0" ] && [ -f "$_port_file" ]; then
+  _real_port=$(cat "$_port_file")
+  if [ -n "$_real_port" ] && [ "$_real_port" != "0" ]; then
+    TT_TEST_PORT=$_real_port
+  fi
+fi
+
 TT_TEST_DB="${TT_WORKTREE_ROOT}/data/test/attendance.db"
 TT_TEST_MODE=1
 TT_BASE_URL="http://127.0.0.1:${TT_TEST_PORT}"
Author	SHA1	Message	Date
s0wlz (Matthias Puchstein)	f97f91781a	fix: use debian:trixie-slim runtime to match builder glibc 2.38 Some checks failed Release / release (push) Failing after 8m35s Details rust:1.95-slim is trixie-based (glibc 2.38); bookworm-slim only has 2.36, causing a crash on startup.	2026-05-05 03:36:22 +02:00
s0wlz (Matthias Puchstein)	99b501d69c	fix: ignore RUSTSEC-2023-0071 in release workflow cargo audit Some checks failed Release / release (push) Failing after 8m30s Details	2026-05-05 03:16:50 +02:00
s0wlz (Matthias Puchstein)	b7d20d9573	chore: ignore screenshot-*.png files Some checks failed Release / release (push) Failing after 2m23s Details	2026-05-05 03:12:23 +02:00
s0wlz (Matthias Puchstein)	39341ce69d	fix: run svelte-kit sync before svelte-check in Docker build Some checks failed CI / test (pull_request) Has been cancelled Details CI / test (push) Successful in 8m19s Details .svelte-kit/tsconfig.json is gitignored and must be generated at build time — svelte-check cannot run without it.	2026-05-05 02:48:40 +02:00
s0wlz (Matthias Puchstein)	ab9d1fc547	fix: track Cargo.lock so Docker CI build can copy it Some checks failed CI / test (pull_request) Has been cancelled Details CI / test (push) Failing after 6m57s Details Cargo.lock was in .gitignore, making it absent from the git checkout that CI builds the Docker image from — COPY backend/Cargo.lock failed.	2026-05-05 02:39:03 +02:00
s0wlz (Matthias Puchstein)	681b43174b	fix: implement random-port discovery for CI E2E backend Some checks failed CI / test (pull_request) Has been cancelled Details CI / test (push) Failing after 4m51s Details When PORT=0, the backend now writes its actual bound port to data/test/.port. test-env.sh reads that file when TT_TEST_PORT=0 so all targets (test-up, test-reset, test-down) resolve the real URL. test-up waits for .port to appear before the health-check loop.	2026-05-05 02:24:29 +02:00
s0wlz (Matthias Puchstein)	24f2556c9d	fix: replace per-element CASE WHEN in migration 003 with WHERE EXISTS Some checks failed CI / test (push) Failing after 3m32s Details CI / test (pull_request) Failing after 3m26s Details Instead of applying a per-element heuristic (skip if value ≤ 50), identify pixel-scale rooms at the row level with WHERE EXISTS, then convert all elements unconditionally. Eliminates the risk of mixed-scale elements within the same room.	2026-05-05 02:02:30 +02:00
s0wlz (Matthias Puchstein)	4939838a7f	fix: address PR #2 review findings across backend and frontend Some checks failed CI / test (push) Failing after 4m9s Details CI / test (pull_request) Failing after 3m26s Details - Makefile: add SHELL := /bin/bash so test-env.sh pipefail works in CI - RoomCanvas: fix onElementClick firing on drag start (now fires on mouseup for click-in-place only); fix Props type to accept null; guard grid pattern against snapStep=0 (invalid SVG); remove unsafe null cast - live/[slotId]: fix studentNamesBySeat $derived wrapping a function instead of a value — reactivity was broken, map never updated - s/[code]: block clicks on occupied seats before hitting the backend; pass occupiedSeatIds to confirmed-view RoomCanvas; clear errorMsg on retry - rooms/+page: replace alert() in deleteRoom with inline errorMsg state - rooms/[roomId]: replace deprecated .substr with .slice - courses.rs: assign_tutor uses fetch_optional → 404 on unknown tutor_id instead of propagating RowNotFound as 500 - rooms.rs: delete_room returns 404 when room does not exist; replace fract() != 0.0 float check with epsilon-based validation - auth_routes.rs: refresh endpoint re-checks is_active so deactivated tutors cannot obtain new access tokens; fix test INSERT to include is_active - tutors.rs: wrap delete_tutor reference checks and DELETE in a transaction - attendance.rs: replace #[allow(clippy::type_complexity)] with type alias - migrations/003: document > 50 heuristic precondition Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>	2026-05-05 01:55:35 +02:00
s0wlz (Matthias Puchstein)	827eb63bab	fix: address review findings — error handling, migration safety, CI audit Some checks failed CI / test (push) Failing after 3m6s Details CI / test (pull_request) Failing after 3m22s Details Backend: - migration 003: apply pixel→grid transform per-element (CASE WHEN > 50) instead of per-row, preventing double-conversion of mixed-scale rooms; skip empty arrays via json_array_length guard to avoid NULL assignment - attendance.rs: log layout JSON parse errors instead of silently swallowing them with .ok() - tutors.rs: check rows_affected() in set_tutor_active and return 404 for non-existent IDs; remap FK constraint errors on delete to 409 so concurrent inserts between conflict-check and DELETE don't surface as 500 Frontend: - live/[slotId]: expose polling failures to the tutor via error banner instead of only console.error - s/[code]: split checkin into two try/catch blocks so a successful POST followed by a failed reload doesn't report failure to the student; fix dead '409' string detection to match actual server error 'seat taken' - rooms/[roomId]: remove duplicate onMount fetch; add .catch() to $effect - tutors: expose loadTutors failures via error banner, not just console - rooms: fix bare catch in createRoom (captures error, shows message); add try/catch to onMount rooms load CI: - sync cargo audit --ignore RUSTSEC-2023-0071 with Makefile; the advisory is in rsa which sqlx-mysql retains in the lock file even when the mysql feature is disabled — aws_lc_rs correctly removes it from the active tree	2026-05-05 01:28:40 +02:00
s0wlz (Matthias Puchstein)	3b9c755e39	feat: unified bug fixes, tutor lifecycle, and room editor refactor Some checks failed CI / test (push) Failing after 10m30s Details CI / test (pull_request) Failing after 7m25s Details - Security: Fixed RUSTSEC-2023-0071 via aws_lc_rs - API: Fixed empty 200 body parsing and check-in typing - Tutors: Added is_active flag, safe deletion with 409 conflict checks, and admin toggle UI - Rooms: Migrated room layouts from pixel to grid scale, added additive layout validators - UI: Improved RoomCanvas with dynamic sizing, interactive editing, snap-to-grid - App: Replaced static SeatMap component with dynamic RoomCanvas across live and checkin views	2026-05-05 00:47:05 +02:00
s0wlz (Matthias Puchstein)	d79c7ed08c	added git worktrees to the plan	2026-05-04 17:26:24 +02:00
s0wlz (Matthias Puchstein)	650f3456cb	some planning and issue finding	2026-05-04 17:15:53 +02:00
				`@@ -0,0 +1 @@`
				`ALTER TABLE tutors ADD COLUMN is_active BOOLEAN NOT NULL DEFAULT 1;`