refactor(web): sweep 24 test files to use makeTrack/makeTracks fixtures (#375)

Replaces inline TrackRef literal redefinitions with calls to the
test-utils helper. Tests that asserted on default field values
(e.g. track titles, artist names rendered in the DOM) keep explicit
overrides; tests that only need a stub for shape now use makeTrack()
with no overrides.

PlaylistCard.test.ts, PlaylistTrackRow.test.ts, and playlist.test.ts
SKIPPED — they use PlaylistTrack (with track_id/added_at), not TrackRef.
ArtistCard.svelte and +page.svelte route files (matched by initial grep)
SKIPPED — live code, not test files.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/src/routes/library/liked/liked.test.ts

@@ -3,6 +3,7 @@ import { render, screen, fireEvent } from '@testing-library/svelte';
 import { mockInfiniteQuery } from '../../../test-utils/query';
 import type { ArtistRef, AlbumRef, TrackRef, Page } from '$lib/api/types';
 import { readable } from 'svelte/store';
+import { makeTrack } from '$test-utils/fixtures/track';
 
 vi.mock('$lib/api/likes', () => ({
   createLikedIdsQuery: () => readable({
@@ -42,12 +43,10 @@ describe('liked library page', () => {
       id: 'al1', title: 'Y', sort_title: 'Y', artist_id: 'a1', artist_name: 'X',
       year: 2020, track_count: 1, duration_sec: 100, cover_url: '/x', cover_art_source: null
     };
-    const tr: TrackRef = {
-      id: 't1', title: 'Z', album_id: 'al1', album_title: 'Y',
-      artist_id: 'a1', artist_name: 'X',
-      track_number: 1, disc_number: 1, duration_sec: 100,
-      stream_url: '/api/tracks/t1/stream'
-    };
+    const tr: TrackRef = makeTrack({
+      title: 'Z', album_id: 'al1', album_title: 'Y',
+      artist_id: 'a1', artist_name: 'X', duration_sec: 100
+    });
     (createLikedArtistsInfiniteQuery as ReturnType<typeof vi.fn>).mockReturnValue(
       mockInfiniteQuery({ pages: [page([ar], 1)] })
     );