feat(search): answer search from a local index; tier downloads by lifetime

Search's instant leg read only downloaded items, so with no downloads it
returned nothing and every keystroke fell through to a full Recursive=true
server query. It now reads the whole synced catalog through the same
availability CTE get_items uses, gated on the same include_catalog_browse
flag so search and browse cannot diverge. (UR-065, DR-108)

Also fixes three defects found while confirming that:

- items_fts grew by a full duplicate index every catalog pass. INSERT OR
  REPLACE fires no AFTER DELETE trigger without recursive_triggers, so the
  old index row was orphaned, and a TEXT PRIMARY KEY meant the replacement
  took a fresh rowid and inserted a second entry. Now a real upsert, with
  migration 021 rebuilding existing indexes. (DR-110)
- DELETE FROM items existed nowhere, so server-side deletions never
  propagated. Adds a post-crawl mark-and-sweep, scoped to crawled types,
  skipping downloaded items, and refusing to run after a partial crawl
  because items.parent_id cascades. (DR-110)
- The index omitted MusicArtist, Playlist and People, which search groups
  results by. Adds them plus people_fts (migration 022). (DR-111)

Re-indexing moves from a frontend startup call to a Rust background task
with a 6h TTL, so a long session no longer searches a stale catalog and a
restart no longer forces a crawl regardless of freshness. (DR-109, IR-030)

Downloads gain a lifetime tier. Eviction selected every completed row by
age with no download_source filter, so hitting the storage limit deleted
the oldest download -- typically one saved deliberately for offline -- to
make room for a precached track. It now reclaims only 'auto' rows, and
expired ones are reclaimed first, before live cache is evicted.
(DR-126, DR-127)

Downloaded video and audio-only handoffs now play from disk instead of
streaming; the video path had never consulted downloads at all. No
transcode is involved: MPV runs video=no and ExoPlayer has no surface for
an Audio item. (DR-123 in part, DR-128)

FTS queries are built as quoted phrases so apostrophes, hyphens and
slashes are data rather than operator syntax, and the item-type filter is
bound rather than interpolated.

Specs: docs/specs/catalog-index-search.md,
docs/specs/read-through-media-cache.md

Includes concurrently-developed favourites browsing and background-audio
stream-end handling; the two workstreams share offline.rs, lib.rs and
online.rs, so no subset of files builds independently.

src-tauri/src/lib.rs

@@ -128,6 +128,8 @@ use commands::{
     player_get_sleep_timer,
     player_get_status,
     player_get_video_settings,
+    // Preload commands
+    player_local_media_path,
     player_move_in_queue,
     player_next,
     player_on_playback_ended,
@@ -138,7 +140,6 @@ use commands::{
     player_play_next_episode,
     player_play_queue,
     player_play_tracks,
-    // Preload commands
     player_preload_upcoming,
     player_previous,
     player_remove_from_queue,
@@ -187,6 +188,7 @@ use commands::{
     repository_get_download_disk_usage,
     repository_get_downloaded_items,
     repository_get_downloaded_libraries,
+    repository_get_favorites,
     repository_get_genres,
     repository_get_image_url,
     repository_get_item,
@@ -700,6 +702,7 @@ fn specta_builder() -> Builder<tauri::Wry> {
             player_report_position,
             player_report_media_loaded,
             // Preload commands
+            player_local_media_path,
             player_preload_upcoming,
             player_set_cache_config,
             player_get_cache_config,
@@ -893,6 +896,7 @@ fn specta_builder() -> Builder<tauri::Wry> {
             repository_get_image_url,
             repository_mark_favorite,
             repository_unmark_favorite,
+            repository_get_favorites,
             repository_get_person,
             repository_get_items_by_person,
             repository_get_similar_items,
@@ -1288,6 +1292,21 @@ pub fn run() {
             let playback_reporter_wrapper = PlaybackReporterWrapper(playback_reporter.clone());
             app.manage(playback_reporter_wrapper);
 
+            // Keep the local search index fresh. Ownership of *when* to re-index
+            // sits here rather than in the frontend: it is sync policy over
+            // domain data, and a startup-only trigger left a long session
+            // searching a stale catalog.
+            // TRACES: UR-065 | DR-109, IR-030
+            info!("[INIT] Starting background catalog indexer...");
+            commands::catalog::spawn_catalog_indexer(app.handle().clone());
+
+            // Push favourite toggles made while the server was unreachable, on
+            // every reconnect. In Rust rather than the frontend so it runs
+            // whether or not the screen that made the change is still mounted.
+            // TRACES: UR-069 | DR-120
+            info!("[INIT] Starting favourites drain...");
+            commands::favorites::spawn_favorites_drain(app.handle().clone());
+
             info!("[INIT] Application setup completed successfully");
             Ok(())
         })