Workstream E (backend): wire tauri-specta — annotate commands, derive Type, generate-ready Builder

- Add #[specta::specta] to all 201 #[tauri::command] functions.
- Derive specta::Type on all IPC DTOs (repository/types, settings, player/storage/
  download command DTOs, player enums, jellyfin SessionInfo/NowPlayingItem/PlayState,
  ThumbnailCacheStats, DownloadInfo, CacheConfig, etc.).
- Replace tauri::generate_handler! with a tauri_specta::Builder + collect_commands!
  in lib.rs (exports bindings.ts in debug builds).

Two contract changes required by specta constraints (frontend migration follows):
- specta caps command arity at 10 args: download_item_and_start / download_item /
  download_video now take a single request struct (params bundled, body unchanged
  via destructuring).
- specta can't parse split serde rename_all: SessionInfo/NowPlayingItem/PlayState
  switched to rename_all = "PascalCase" (Jellyfin deserialization preserved; these
  now serialize PascalCase to the frontend).

cargo check --lib is clean (0 errors). Frontend migration to bindings.ts is the next step.

src-tauri/src/commands/repository.rs

@@ -48,6 +48,7 @@ pub struct RepositoryManagerWrapper(pub RepositoryManager);
 /// Create a new repository instance
 /// Returns a handle (UUID) for accessing the repository
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_create(
     manager: State<'_, RepositoryManagerWrapper>,
     db: State<'_, crate::commands::storage::DatabaseWrapper>,
@@ -108,6 +109,7 @@ pub async fn repository_create(
 
 /// Destroy a repository instance
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_destroy(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -118,6 +120,7 @@ pub async fn repository_destroy(
 
 /// Get libraries
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_libraries(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -138,6 +141,7 @@ pub async fn repository_get_libraries(
 
 /// Get items in a container (library, folder, album, etc.)
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_items(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -152,6 +156,7 @@ pub async fn repository_get_items(
 
 /// Get a single item by ID
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_item(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -165,6 +170,7 @@ pub async fn repository_get_item(
 
 /// Get latest items in a library
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_latest_items(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -179,6 +185,7 @@ pub async fn repository_get_latest_items(
 
 /// Get resume items (continue watching/listening)
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_resume_items(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -201,6 +208,7 @@ pub async fn repository_get_resume_items(
 
 /// Get next up episodes
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_next_up_episodes(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -215,6 +223,7 @@ pub async fn repository_get_next_up_episodes(
 
 /// Get recently played audio
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_recently_played_audio(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -228,6 +237,7 @@ pub async fn repository_get_recently_played_audio(
 
 /// Get resume movies
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_resume_movies(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -241,6 +251,7 @@ pub async fn repository_get_resume_movies(
 
 /// Get genres for a library
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_genres(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -254,6 +265,7 @@ pub async fn repository_get_genres(
 
 /// Search for items
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_search(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -268,6 +280,7 @@ pub async fn repository_search(
 
 /// Get playback info for an item
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_playback_info(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -281,6 +294,7 @@ pub async fn repository_get_playback_info(
 
 /// Get video stream URL with optional seeking support
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_video_stream_url(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -303,6 +317,7 @@ pub async fn repository_get_video_stream_url(
 
 /// Get audio stream URL for a track
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_audio_stream_url(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -317,6 +332,7 @@ pub async fn repository_get_audio_stream_url(
 
 /// Report playback start
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_report_playback_start(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -331,6 +347,7 @@ pub async fn repository_report_playback_start(
 
 /// Report playback progress
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_report_playback_progress(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -345,6 +362,7 @@ pub async fn repository_report_playback_progress(
 
 /// Report playback stopped
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_report_playback_stopped(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -359,6 +377,7 @@ pub async fn repository_report_playback_stopped(
 
 /// Get image URL for an item
 #[tauri::command]
+#[specta::specta]
 pub fn repository_get_image_url(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -372,6 +391,7 @@ pub fn repository_get_image_url(
 
 /// Get subtitle URL for a media item
 #[tauri::command]
+#[specta::specta]
 #[allow(dead_code)]
 pub fn repository_get_subtitle_url(
     manager: State<'_, RepositoryManagerWrapper>,
@@ -387,6 +407,7 @@ pub fn repository_get_subtitle_url(
 
 /// Get video download URL with quality preset
 #[tauri::command]
+#[specta::specta]
 #[allow(dead_code)]
 pub fn repository_get_video_download_url(
     manager: State<'_, RepositoryManagerWrapper>,
@@ -401,6 +422,7 @@ pub fn repository_get_video_download_url(
 
 /// Mark an item as favorite
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_mark_favorite(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -414,6 +436,7 @@ pub async fn repository_mark_favorite(
 
 /// Unmark an item as favorite
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_unmark_favorite(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -427,6 +450,7 @@ pub async fn repository_unmark_favorite(
 
 /// Get person details
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_person(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -440,6 +464,7 @@ pub async fn repository_get_person(
 
 /// Get items by person (actor, director, etc.)
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_items_by_person(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,
@@ -454,6 +479,7 @@ pub async fn repository_get_items_by_person(
 
 /// Get similar/related items for a media item
 #[tauri::command]
+#[specta::specta]
 pub async fn repository_get_similar_items(
     manager: State<'_, RepositoryManagerWrapper>,
     handle: String,