feat(library): focused music/TV/movie landing screens + self-draining download queue

Library screens:
- Add dedicated music, TV, and movie landing pages (hero banner +
  horizontal carousels) backed by new music/tv/movies stores.
- Route tvshows libraries to /library/tv; surface rediscover ("haven't
  listened to in a while") albums via a new repository method across
  online/offline/hybrid repos plus the repository_get_rediscover_albums
  command.
- Add an A-Z jump bar for long alphabetically-sorted lists, with grid
  index anchors in LibraryGrid/LibraryListView/TrackList.
- Filter the "Podcasts" folder out of music library queries.

Downloads:
- Add a backend queue pump: enqueue_download / enqueue_video_downloads
  persist the resolved stream URL + target dir on each row (migration
  017), and the pump starts up to max_concurrent and drains the rest
  automatically as slots free, instead of the frontend silently dropping
  items past the concurrency limit. Album/series/season buttons now
  enqueue rather than calling start_download directly.

Other fixes:
- Hybrid search now returns instant cache results and pushes the merged
  cache+server union via a request-id-tagged search-event, so superseded
  queries can't clobber fresher results.
- URL-encode SearchTerm / genres / item types in online repo requests.
- Android: pause on audio-becoming-noisy (headphone/BT disconnect).

src/routes/library/tv/shows/+page.svelte

@@ -0,0 +1,27 @@
+<script lang="ts">
+  import GenericMediaListPage from "$lib/components/library/GenericMediaListPage.svelte";
+
+  /**
+   * TV show browser (all series)
+   * @req: UR-007 - Navigate media in library
+   * @req: UR-008 - Search media across libraries
+   * @req: DR-007 - Library browsing screens
+   */
+
+  const config = {
+    itemType: "Series" as const,
+    title: "TV Shows",
+    backPath: "/library/tv",
+    searchPlaceholder: "Search shows...",
+    sortOptions: [
+      { key: "SortName", label: "A-Z" },
+      { key: "ProductionYear", label: "Year" },
+      { key: "DateCreated", label: "Recently Added" },
+      { key: "CommunityRating", label: "Rating" },
+    ],
+    defaultSort: "SortName",
+    displayComponent: "grid" as const,
+  };
+</script>
+
+<GenericMediaListPage {config} />