feat(web): saisonal admin curator + homepage uses /season/markets

- New admin page at /admin/saisonal: split layout with current selection
  on the left (reorderable + removable) and chronological suggestions on
  the right (one-click pin). Count input (1..24). Server action PUTs the
  full config in one shot.
- Admin sidebar: new 'Saisonal' link between 'Märkte' and 'Discovery'.
- Homepage seasonMarkets fetch switched from /markets?from=today&per_page=6
  to /season/markets so the curated order is what users actually see.

web/src/routes/(public)/+page.server.ts

@@ -18,7 +18,7 @@ export const load: PageServerLoad = async ({ fetch }) => {
 
 	const [weekendRes, seasonRes, statsRes] = await Promise.allSettled([
 		apiFetch<MarketSummary[]>(`/markets?from=${fromDate}&to=${weekendTo}&per_page=4`, { fetch }),
-		apiFetch<MarketSummary[]>(`/markets?from=${fromDate}&per_page=6`, { fetch }),
+		apiFetch<MarketSummary[]>('/season/markets', { fetch }),
 		apiFetch<MarketStats>('/markets/stats', { fetch }),
 	]);
 

web/src/routes/(public)/admin/+layout.svelte

@@ -10,6 +10,7 @@
 
 	const navItems = [
 		{ href: '/admin/maerkte', label: 'Märkte' },
+		{ href: '/admin/saisonal', label: 'Saisonal' },
 		{ href: '/admin/discovery', label: 'Discovery' },
 		{ href: '/admin/einstellungen', label: 'Einstellungen' },
 	];

web/src/routes/(public)/admin/saisonal/+page.server.ts

@@ -0,0 +1,59 @@
+import { fail } from '@sveltejs/kit';
+import { serverFetch } from '$lib/api/client.server.js';
+import type { MarketSummary } from '$lib/api/types.js';
+import type { Actions, PageServerLoad } from './$types.js';
+
+interface SeasonConfig {
+	slugs: string[];
+	count: number;
+}
+
+export const load: PageServerLoad = async ({ cookies, fetch }) => {
+	const [cfgRes, suggestionsRes] = await Promise.all([
+		serverFetch<SeasonConfig>('/admin/settings/season', cookies, { fetch }).catch(() => null),
+		serverFetch<MarketSummary[]>('/admin/season/suggestions', cookies, { fetch }).catch(
+			() => null,
+		),
+	]);
+
+	const config: SeasonConfig = cfgRes?.data ?? { slugs: [], count: 6 };
+	const allSuggestions: MarketSummary[] = suggestionsRes?.data ?? [];
+
+	const pinnedSet = new Set(config.slugs);
+	const pinnedMap = new Map(allSuggestions.map((m) => [m.slug, m]));
+	const pinned: MarketSummary[] = config.slugs
+		.map((slug) => pinnedMap.get(slug))
+		.filter((m): m is MarketSummary => Boolean(m));
+	const suggestions = allSuggestions.filter((m) => !pinnedSet.has(m.slug));
+
+	return { config, pinned, suggestions };
+};
+
+export const actions: Actions = {
+	save: async ({ cookies, fetch, request }) => {
+		const data = await request.formData();
+		const slugsRaw = data.get('slugs');
+		const countRaw = data.get('count');
+
+		if (typeof slugsRaw !== 'string' || typeof countRaw !== 'string') {
+			return fail(400, { error: 'Ungültige Eingabe.' });
+		}
+
+		const slugs = slugsRaw.split(',').map((s) => s.trim()).filter(Boolean);
+		const count = parseInt(countRaw, 10);
+		if (!Number.isFinite(count) || count < 1 || count > 24) {
+			return fail(400, { error: 'Anzahl muss zwischen 1 und 24 liegen.' });
+		}
+
+		try {
+			await serverFetch('/admin/settings/season', cookies, {
+				method: 'PUT',
+				body: JSON.stringify({ slugs, count }),
+				fetch,
+			});
+			return { success: true };
+		} catch (err) {
+			return fail(500, { error: err instanceof Error ? err.message : 'Fehler beim Speichern.' });
+		}
+	},
+};

web/src/routes/(public)/admin/saisonal/+page.svelte

@@ -0,0 +1,234 @@
+<script lang="ts">
+	import { enhance } from '$app/forms';
+	import type { ActionData, PageData } from './$types.js';
+	import type { MarketSummary } from '$lib/api/types.js';
+
+	interface Props {
+		data: PageData;
+		form: ActionData;
+	}
+
+	let { data, form }: Props = $props();
+
+	// Wrap data reads in closures so the $state initializers don't trip the
+	// state_referenced_locally warning — we explicitly want the snapshot at
+	// mount; load reruns after save are folded back via form result.
+	const snapshotPinned = (): MarketSummary[] => [...data.pinned];
+	const snapshotSuggestions = (): MarketSummary[] => [...data.suggestions];
+	const snapshotCount = (): number => data.config.count;
+
+	let pinned = $state<MarketSummary[]>(snapshotPinned());
+	let suggestions = $state<MarketSummary[]>(snapshotSuggestions());
+	let count = $state(snapshotCount());
+	let saving = $state(false);
+
+	function add(market: MarketSummary) {
+		pinned = [...pinned, market];
+		suggestions = suggestions.filter((s) => s.slug !== market.slug);
+	}
+
+	function remove(slug: string) {
+		const removed = pinned.find((m) => m.slug === slug);
+		pinned = pinned.filter((m) => m.slug !== slug);
+		if (removed) suggestions = [removed, ...suggestions];
+	}
+
+	function move(slug: string, delta: -1 | 1) {
+		const idx = pinned.findIndex((m) => m.slug === slug);
+		const target = idx + delta;
+		if (idx < 0 || target < 0 || target >= pinned.length) return;
+		const next = [...pinned];
+		[next[idx], next[target]] = [next[target], next[idx]];
+		pinned = next;
+	}
+
+	function fmtDateRange(from: string, to: string): string {
+		const fmt = (iso: string) =>
+			new Date(iso).toLocaleDateString('de-DE', {
+				day: '2-digit',
+				month: 'short',
+				timeZone: 'UTC',
+			});
+		return from === to ? fmt(from) : `${fmt(from)} – ${fmt(to)}`;
+	}
+</script>
+
+<div class="space-y-6">
+	<div>
+		<h1 class="text-2xl font-bold text-stone-900 dark:text-stone-100">Saisonale Märkte</h1>
+		<p class="mt-1 text-sm text-stone-500 dark:text-stone-400">
+			Wähle die Märkte, die auf der Startseite hervorgehoben werden. Fehlende Plätze werden mit
+			kommenden Märkten in chronologischer Reihenfolge aufgefüllt.
+		</p>
+	</div>
+
+	{#if form?.success}
+		<div
+			class="border-l-2 border-emerald-500 bg-emerald-50 p-3 text-sm text-emerald-900 dark:bg-emerald-900/30 dark:text-emerald-100"
+		>
+			Gespeichert.
+		</div>
+	{:else if form?.error}
+		<div
+			class="border-l-2 border-red-500 bg-red-50 p-3 text-sm text-red-900 dark:bg-red-900/30 dark:text-red-100"
+		>
+			{form.error}
+		</div>
+	{/if}
+
+	<form
+		method="POST"
+		action="?/save"
+		use:enhance={() => {
+			saving = true;
+			return async ({ update }) => {
+				saving = false;
+				await update();
+			};
+		}}
+	>
+		<input type="hidden" name="slugs" value={pinned.map((m) => m.slug).join(',')} />
+		<input type="hidden" name="count" value={count} />
+
+		<div class="grid grid-cols-1 gap-6 md:grid-cols-2">
+			<!-- Pinned -->
+			<section class="border border-stone-200 dark:border-stone-700">
+				<header
+					class="flex items-center justify-between border-b border-stone-200 px-4 py-3 dark:border-stone-700"
+				>
+					<h2
+						class="text-sm font-semibold tracking-wide text-stone-700 uppercase dark:text-stone-300"
+					>
+						Aktuelle Auswahl ({pinned.length})
+					</h2>
+					<label class="flex items-center gap-2 text-xs text-stone-500 dark:text-stone-400">
+						Anzeigen:
+						<input
+							type="number"
+							min="1"
+							max="24"
+							bind:value={count}
+							class="w-16 border border-stone-300 px-2 py-1 text-xs dark:border-stone-600 dark:bg-stone-800"
+						/>
+					</label>
+				</header>
+
+				{#if pinned.length === 0}
+					<p class="p-4 text-sm italic text-stone-500 dark:text-stone-400">
+						Noch keine Märkte ausgewählt. Klicke auf einen Vorschlag rechts.
+					</p>
+				{:else}
+					<ul>
+						{#each pinned as market, i}
+							<li
+								class="flex items-start gap-3 border-b border-stone-100 px-4 py-3 last:border-0 dark:border-stone-800"
+							>
+								<span
+									class="mt-0.5 w-5 shrink-0 font-mono text-xs text-stone-400 dark:text-stone-500"
+								>
+									{i + 1}.
+								</span>
+								<div class="flex-1 min-w-0">
+									<div class="text-sm font-medium text-stone-900 dark:text-stone-100">
+										{market.name}
+									</div>
+									<div class="text-xs text-stone-500 dark:text-stone-400">
+										{market.city} · {market.state} · {
+											fmtDateRange(
+												market.start_date,
+												market.end_date,
+											)
+										}
+									</div>
+								</div>
+								<div class="flex shrink-0 gap-1">
+									<button
+										type="button"
+										onclick={() => move(market.slug, -1)}
+										disabled={i === 0}
+										aria-label="Nach oben"
+										class="px-2 py-1 text-stone-500 hover:text-stone-900 disabled:opacity-30 dark:hover:text-stone-100"
+									>
+										↑
+									</button>
+									<button
+										type="button"
+										onclick={() => move(market.slug, 1)}
+										disabled={i === pinned.length - 1}
+										aria-label="Nach unten"
+										class="px-2 py-1 text-stone-500 hover:text-stone-900 disabled:opacity-30 dark:hover:text-stone-100"
+									>
+										↓
+									</button>
+									<button
+										type="button"
+										onclick={() => remove(market.slug)}
+										aria-label="Entfernen"
+										class="px-2 py-1 text-stone-500 hover:text-red-600 dark:hover:text-red-400"
+									>
+										×
+									</button>
+								</div>
+							</li>
+						{/each}
+					</ul>
+				{/if}
+			</section>
+
+			<!-- Suggestions -->
+			<section class="border border-stone-200 dark:border-stone-700">
+				<header class="border-b border-stone-200 px-4 py-3 dark:border-stone-700">
+					<h2
+						class="text-sm font-semibold tracking-wide text-stone-700 uppercase dark:text-stone-300"
+					>
+						Vorschläge — kommende Märkte ({suggestions.length})
+					</h2>
+				</header>
+				{#if suggestions.length === 0}
+					<p class="p-4 text-sm italic text-stone-500 dark:text-stone-400">
+						Keine weiteren Vorschläge verfügbar.
+					</p>
+				{:else}
+					<ul class="max-h-[600px] overflow-y-auto">
+						{#each suggestions as market}
+							<li
+								class="flex items-start gap-3 border-b border-stone-100 px-4 py-3 last:border-0 dark:border-stone-800"
+							>
+								<div class="flex-1 min-w-0">
+									<div class="text-sm font-medium text-stone-900 dark:text-stone-100">
+										{market.name}
+									</div>
+									<div class="text-xs text-stone-500 dark:text-stone-400">
+										{market.city} · {market.state} · {
+											fmtDateRange(
+												market.start_date,
+												market.end_date,
+											)
+										}
+									</div>
+								</div>
+								<button
+									type="button"
+									onclick={() => add(market)}
+									class="shrink-0 border border-stone-300 px-3 py-1 text-xs font-medium text-stone-700 hover:bg-stone-100 dark:border-stone-600 dark:text-stone-300 dark:hover:bg-stone-800"
+								>
+									+ Pin
+								</button>
+							</li>
+						{/each}
+					</ul>
+				{/if}
+			</section>
+		</div>
+
+		<div class="mt-6 flex justify-end">
+			<button
+				type="submit"
+				disabled={saving}
+				class="border border-stone-900 bg-stone-900 px-5 py-2 text-sm font-medium text-white hover:bg-stone-800 disabled:opacity-50 dark:border-stone-100 dark:bg-stone-100 dark:text-stone-900 dark:hover:bg-stone-200"
+			>
+				{saving ? 'Speichere…' : 'Auswahl speichern'}
+			</button>
+		</div>
+	</form>
+</div>