docs: update Rune plugin guide with working Item API, manifest providers, logging

docs/PLUGIN_DEVELOPMENT.md

@@ -419,49 +419,92 @@ owlry.provider.register({
 
 ## Rune Plugin API
 
-Rune plugins use a Rust-like syntax with memory safety.
+Rune plugins use a Rust-like syntax with memory safety. Requires `owlry-rune` runtime.
+
+```bash
+# Install Rune runtime
+yay -S owlry-rune
+
+# Create plugin directory
+mkdir -p ~/.config/owlry/plugins/my-rune-plugin
+```
 
 ### Plugin Manifest
 
+Rune plugins declare providers in `[[providers]]` sections of `plugin.toml`. The runtime reads these declarations and maps them to the plugin's `refresh()` and `query()` functions.
+
 ```toml
 [plugin]
 id = "my-rune-plugin"
 name = "My Rune Plugin"
 version = "1.0.0"
-entry = "main.rn"
+description = "A custom Rune plugin"
+entry = "main.rn"              # Default: main.rn; entry_point also accepted
 
 [[providers]]
-id = "runeprovider"
-name = "Rune Provider"
-type = "static"
+id = "myrune"
+name = "My Rune Provider"
+prefix = ":myrune"             # Activates with :myrune prefix in search
+icon = "application-x-executable"
+type = "static"                # "static" (refresh at startup) or "dynamic" (query per keystroke)
+type_id = "myrune"             # Short ID shown as badge in UI
 ```
 
 ### Rune API
 
 ```rune
-use owlry::{Item, log, notify};
+use owlry::Item;
 
+/// Called once at startup and on each hot-reload for static providers
 pub fn refresh() {
     let items = [];
 
-    items.push(Item::new("id", "Name", "command")
-        .description("Description")
-        .icon("icon-name"));
+    items.push(Item::new("item-1", "Hello from Rune", "echo 'Hello!'")
+        .description("A Rune greeting")
+        .icon("face-smile")
+        .keywords(["hello", "rune"]));
+
+    items.push(Item::new("item-2", "Another Item", "notify-send 'Hi'")
+        .description("Send a notification")
+        .icon("dialog-information"));
 
     items
 }
 
+/// Called per keystroke for dynamic providers
 pub fn query(q) {
     if q.is_empty() {
         return [];
     }
 
-    log::info(`Query: {q}`);
-
-    [Item::new("result", `Result: {q}`, `echo {q}`)]
+    [Item::new("result", `Result: {q}`, `echo {q}`)
+        .description("Search result")]
 }
 ```
 
+### Item Builder
+
+The `Item` type is provided by the `owlry` module:
+
+```rune
+// Create an item with required fields
+let item = Item::new(id, name, command);
+
+// Optional builder methods (all return Item for chaining)
+item = item.description("Description text");
+item = item.icon("icon-name");           // Freedesktop icon name
+item = item.keywords(["tag1", "tag2"]);  // Search keywords
+```
+
+### Logging
+
+```rune
+owlry::log_info("Info message");
+owlry::log_warn("Warning message");
+owlry::log_error("Error message");
+owlry::log_debug("Debug message");
+```
+
 ---
 
 ## Best Practices
@@ -489,19 +532,22 @@ extern "C" fn provider_refresh(handle: ProviderHandle) -> RVec<PluginItem> {
 ```
 
 ```lua
--- Lua: Wrap in pcall for safety
-function refresh()
-    local ok, result = pcall(function()
-        return load_items()
-    end)
+-- Lua: Wrap refresh callback in pcall for safety
+owlry.provider.register({
+    name = "safe-provider",
+    refresh = function()
+        local ok, result = pcall(function()
+            return load_items()
+        end)
 
-    if not ok then
-        owlry.log.error("Failed: " .. result)
-        return {}
-    end
+        if not ok then
+            owlry.log.error("Failed: " .. result)
+            return {}
+        end
 
-    return result
-end
+        return result
+    end,
+})
 ```
 
 ### Icons