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/lib/components/PlayerBar.test.ts

@@ -3,6 +3,7 @@ import { render, screen, fireEvent } from '@testing-library/svelte';
 import type { TrackRef } from '$lib/api/types';
 import { emptyLikesMock } from '../../test-utils/mocks/likes';
 import { emptyQuarantineMock } from '../../test-utils/mocks/quarantine';
+import { makeTrack } from '$test-utils/fixtures/track';
 
 // Mutable state the mocked store reads from.
 const state = vi.hoisted(() => ({
@@ -57,13 +58,12 @@ import {
 } from '$lib/player/store.svelte';
 
 function track(): TrackRef {
-  return {
-    id: 't1', title: 'So What',
+  return makeTrack({
+    title: 'So What',
     album_id: 'xyz', album_title: 'Kind of Blue',
     artist_id: 'md', artist_name: 'Miles Davis',
-    track_number: 1, disc_number: 1,
-    duration_sec: 545, stream_url: '/api/tracks/t1/stream'
-  };
+    duration_sec: 545
+  });
 }
 
 beforeEach(() => {