domain: flip catalog frontend off Jellyfin item-type strings (phase 2a)

Migrate catalog MediaItem consumers from stringly item.type ("Audio",
"MusicAlbum", …) to the neutral item.kind enum across all classification
logic: home, library detail, player routing, artist/person/related/genre
components, tv store.

Model refinements found during migration (each a real distinction the
flat item_type collapsed):
- MediaKind::LiveChannel — live TV (playable, non-seekable) vs
- MediaKind::ChannelItem — channel VOD leaf (playable, seekable) vs
- MediaKind::Channel — channel container (drill-in).
  TvChannel->LiveChannel, non-folder ChannelFolderItem->ChannelItem.

RelatedItemsSection and GenreTags props migrated from Jellyfin type
strings to MediaKind; MediaKind re-exported from api/types.

Deferred by design: display {item.type} text, ResultsCounter labels,
Person.type (role), stream.type (phase 4), and all runTimeTicks/tick math
(coupled to playbackPositionTicks — phase 3). Old fields still dual-carried
so nothing breaks.

Rust 456 + 7 domain tests, frontend 644 tests, check clean.

src/lib/components/library/ArtistDetailView.svelte

@@ -43,7 +43,7 @@
           sortBy: "DateCreated",
           sortOrder: "Descending"
         });
-        albums = albumsResult.items.filter(item => item.type === "MusicAlbum");
+        albums = albumsResult.items.filter(item => item.kind === "album");
       } catch (e) {
         console.warn("Failed to load albums:", e);
       } finally {
@@ -58,7 +58,7 @@
           sortBy: "CommunityRating",
           sortOrder: "Descending"
         });
-        topTracks = tracksResult.items.filter(item => item.type === "Audio");
+        topTracks = tracksResult.items.filter(item => item.kind === "track");
       } catch (e) {
         console.warn("Failed to load tracks:", e);
       } finally {
@@ -76,7 +76,7 @@
             sortOrder: "Descending"
           });
           relatedArtists = relatedResult.items
-            .filter(item => item.id !== artist.id && item.type === "MusicArtist")
+            .filter(item => item.id !== artist.id && item.kind === "artist")
             .slice(0, 6);
         }
       } catch (e) {

src/lib/components/library/GenreTags.svelte

@@ -1,32 +1,35 @@
 <script lang="ts">
   import { goto } from "$app/navigation";
 
+  import type { MediaKind } from "$lib/api/types";
+
   interface Props {
     genres: string[];
     maxShow?: number;  // Default: unlimited
     clickable?: boolean;  // Default: true
-    itemType?: string;  // Determines which genre browse page to open
+    itemKind?: MediaKind;  // Determines which genre browse page to open
   }
 
   let {
     genres,
     maxShow,
     clickable = true,
-    itemType
+    itemKind
   }: Props = $props();
 
-  // Map the item type to its genre-browse route
-  function genreBasePath(type: string | undefined): string {
-    switch (type) {
-      case "MusicAlbum":
-      case "MusicArtist":
-      case "Audio":
+  // Map the item kind to its genre-browse route
+  function genreBasePath(kind: MediaKind | undefined): string {
+    switch (kind) {
+      case "album":
+      case "artist":
+      case "track":
+      case "playlist":
         return "/library/music/genres";
-      case "Series":
-      case "Season":
-      case "Episode":
+      case "series":
+      case "season":
+      case "episode":
         return "/library/shows/genres";
-      case "Movie":
+      case "movie":
         return "/library/movies/genres";
       default:
         return "/library/movies/genres";
@@ -43,7 +46,7 @@
 
   function handleGenreClick(genre: string) {
     if (clickable) {
-      goto(`${genreBasePath(itemType)}?genre=${encodeURIComponent(genre)}`);
+      goto(`${genreBasePath(itemKind)}?genre=${encodeURIComponent(genre)}`);
     }
   }
 </script>

src/lib/components/library/MediaCard.svelte

@@ -101,11 +101,11 @@
   };
 
   const isMusicType = $derived(
-    "type" in item && (item.type === "Audio" || item.type === "MusicAlbum" || item.type === "MusicArtist" || item.type === "Playlist")
+    "kind" in item && (item.kind === "track" || item.kind === "album" || item.kind === "artist" || item.kind === "playlist")
   );
 
   const aspectRatio = $derived(() => {
-    if ("type" in item) {
+    if ("kind" in item) {
       return isMusicType ? "aspect-square" : "aspect-[2/3]";
     }
     // Library

src/lib/components/library/PersonDetailView.svelte

@@ -31,8 +31,8 @@
       });
 
       // Separate movies and series
-      movies = result.items.filter(item => item.type === "Movie");
-      series = result.items.filter(item => item.type === "Series");
+      movies = result.items.filter(item => item.kind === "movie");
+      series = result.items.filter(item => item.kind === "series");
     } catch (e) {
       console.error("Failed to load filmography:", e);
     } finally {

src/lib/components/library/RelatedItemsSection.svelte

@@ -2,12 +2,12 @@
   import { onMount } from "svelte";
   import { goto } from "$app/navigation";
   import { auth } from "$lib/stores/auth";
-  import type { MediaItem, Person } from "$lib/api/types";
+  import type { MediaItem, MediaKind, Person } from "$lib/api/types";
   import MediaCard from "./MediaCard.svelte";
 
   interface Props {
     currentItemId: string;
-    itemType: "Movie" | "Series" | "MusicAlbum" | "Audio";
+    itemKind: MediaKind;
     genres?: string[];
     people?: Person[];
     artistIds?: string[];
@@ -16,7 +16,7 @@
 
   let {
     currentItemId,
-    itemType,
+    itemKind,
     genres = [],
     people = [],
     artistIds = [],
@@ -45,9 +45,9 @@
 
       let items: MediaItem[] = [];
 
-      // First, try to use the Jellyfin Similar Items API (preferred method)
+      // First, try to use the Similar Items API (preferred method)
       // This works for Movies and Series (most common cases)
-      if (["Movie", "Series"].includes(itemType)) {
+      if (itemKind === "movie" || itemKind === "series") {
         try {
           const result = await repo.getSimilarItems(currentItemId, limit);
           items = result.items.filter(item => item.id !== currentItemId);
@@ -65,10 +65,14 @@
       // Fallback: Load by genres using search (works for all item types)
       if (genres && genres.length > 0) {
         try {
-          // Search by first genre to find related items
+          // Search by first genre to find related items. This single-kind query
+          // maps the neutral kind to the concrete Jellyfin item type it needs.
           const searchTerm = genres[0];
+          const itemTypeForKind: Record<string, string> = {
+            movie: "Movie", series: "Series", album: "MusicAlbum", track: "Audio", artist: "MusicArtist",
+          };
           const result = await repo.search(searchTerm, {
-            includeItemTypes: itemType === "MusicAlbum" ? ["MusicAlbum"] : itemType === "Audio" ? ["Audio"] : [itemType],
+            includeItemTypes: [itemTypeForKind[itemKind] ?? "Movie"],
             limit: limit * 2
           });
 
@@ -79,7 +83,7 @@
       }
 
       // For music albums, also try to load by artist (if we don't have enough from similar API)
-      if (itemType === "MusicAlbum" && artistIds && artistIds.length > 0 && items.length === 0) {
+      if (itemKind === "album" && artistIds && artistIds.length > 0 && items.length === 0) {
         try {
           // Search for other albums by artist name from first artist
           const result = await repo.search(artistIds[0], {
@@ -109,14 +113,14 @@
   }
 
   function getTitle(): string {
-    switch (itemType) {
-      case "Movie":
+    switch (itemKind) {
+      case "movie":
         return "Related Movies";
-      case "Series":
+      case "series":
         return "Related Shows";
-      case "MusicAlbum":
+      case "album":
         return "Related Albums";
-      case "Audio":
+      case "track":
         return "Related Tracks";
       default:
         return "Related Items";
@@ -133,7 +137,7 @@
 
   {#if loading}
     <!-- Skeleton loading state -->
-    {@const isMusicContent = itemType === "MusicAlbum" || itemType === "Audio"}
+    {@const isMusicContent = itemKind === "album" || itemKind === "track"}
     <div class="grid grid-cols-2 md:grid-cols-6 gap-4">
       {#each Array(6) as _}
         <div class="animate-pulse">