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  cache+server union via a request-id-tagged search-event, so superseded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/lib/components/library/GenericMediaListPage.svelte

@@ -4,6 +4,8 @@
   import { goto } from "$app/navigation";
   import { currentLibrary } from "$lib/stores/library";
   import { auth } from "$lib/stores/auth";
+  import { shouldShowAudioMiniPlayer } from "$lib/stores/player";
+  import { isAndroid } from "$lib/stores/appState";
   import SearchBar from "$lib/components/common/SearchBar.svelte";
   import SortButtonGroup from "$lib/components/common/SortButtonGroup.svelte";
   import type { SortOption } from "$lib/components/common/SortButtonGroup.svelte";
@@ -13,6 +15,8 @@
   import type { MediaItem, Library, ItemType } from "$lib/api/types";
   import LibraryGrid from "./LibraryGrid.svelte";
   import TrackList from "./TrackList.svelte";
+  import AlphabetScrollBar from "./AlphabetScrollBar.svelte";
+  import { excludePodcasts } from "$lib/utils/podcastFilter";
 
   /**
    * Generic media list page supporting Albums, Artists, Playlists, and Tracks
@@ -41,6 +45,7 @@
 
   let items = $state<MediaItem[]>([]);
   let loading = $state(true);
+  let gridWrapper = $state<HTMLDivElement | null>(null);
   let searchQuery = $state("");
   let debouncedSearchQuery = $state("");
   let sortBy = $state<string>("");
@@ -74,12 +79,13 @@
       const repo = auth.getRepository();
 
       // Use backend search if search query is provided, otherwise use getItems with sort
+      // HACK: excludePodcasts drops the "Podcasts" folder stored in the music library.
       if (debouncedSearchQuery.trim()) {
         const result = await repo.search(debouncedSearchQuery, {
           includeItemTypes: [config.itemType],
           limit: 10000,
         });
-        items = result.items;
+        items = excludePodcasts(result.items);
       } else {
         const result = await repo.getItems($currentLibrary.id, {
           includeItemTypes: [config.itemType],
@@ -88,7 +94,7 @@
           recursive: true,
           limit: 10000,
         });
-        items = result.items;
+        items = excludePodcasts(result.items);
       }
     } catch (e) {
       console.error(`Failed to load ${config.itemType}:`, e);
@@ -142,6 +148,54 @@
       goto(`/library/${track.id}`);
     }
   }
+
+  // ===== A-Z jump bar =====
+  // Bucket a name to its index letter: A-Z, or "#" for digits/symbols/empty.
+  function letterFor(name: string): string {
+    const first = (name ?? "").trim().charAt(0).toUpperCase();
+    return first >= "A" && first <= "Z" ? first : "#";
+  }
+
+  // Only meaningful when the list is sorted alphabetically and long enough to scroll.
+  const isAlphaSorted = $derived(sortBy === "SortName");
+  const showAlphaBar = $derived(
+    isAlphaSorted &&
+      !loading &&
+      !debouncedSearchQuery.trim() &&
+      items.length > 30
+  );
+
+  const availableLetters = $derived.by(() => {
+    const set = new Set<string>();
+    if (showAlphaBar) {
+      for (const item of items) set.add(letterFor(item.name));
+    }
+    return set;
+  });
+
+  // First item index for each letter, honouring current ascending/descending order.
+  const firstIndexForLetter = $derived.by(() => {
+    const map = new Map<string, number>();
+    items.forEach((item, index) => {
+      const letter = letterFor(item.name);
+      if (!map.has(letter)) map.set(letter, index);
+    });
+    return map;
+  });
+
+  function jumpToLetter(letter: string) {
+    const index = firstIndexForLetter.get(letter);
+    if (index === undefined || !gridWrapper) return;
+    const target = gridWrapper.querySelector(`[data-grid-index="${index}"]`);
+    target?.scrollIntoView({ behavior: "smooth", block: "start" });
+  }
+
+  // Bottom space the layout's <main> reserves for the nav / mini-player bars.
+  // Mirrors src/routes/library/+layout.svelte so the A-Z strip ends just above
+  // whichever bars are visible.
+  const bottomGap = $derived(
+    $shouldShowAudioMiniPlayer ? ($isAndroid ? "11rem" : "7rem") : "5rem"
+  );
 </script>
 
 <div class="space-y-6">
@@ -192,10 +246,19 @@
       <p>No {config.title.toLowerCase()} found</p>
     </div>
   {:else}
-    {#if config.displayComponent === "grid"}
-      <LibraryGrid items={items} onItemClick={handleItemClick} musicContent={["MusicAlbum", "MusicArtist", "Audio", "Playlist"].includes(config.itemType)} />
-    {:else if config.displayComponent === "tracklist"}
-      <TrackList tracks={items} onTrackClick={handleTrackClick} />
-    {/if}
+    <div class="flex gap-2">
+      <div bind:this={gridWrapper} class="flex-1 min-w-0">
+        {#if config.displayComponent === "grid"}
+          <LibraryGrid items={items} onItemClick={handleItemClick} musicContent={["MusicAlbum", "MusicArtist", "Audio", "Playlist"].includes(config.itemType)} />
+        {:else if config.displayComponent === "tracklist"}
+          <TrackList tracks={items} onTrackClick={handleTrackClick} />
+        {/if}
+      </div>
+      {#if showAlphaBar}
+        <div class="sticky top-2 self-start flex-shrink-0 h-fit">
+          <AlphabetScrollBar {availableLetters} onJump={jumpToLetter} {bottomGap} />
+        </div>
+      {/if}
+    </div>
   {/if}
 </div>