refactor(web): extract emptyPlaylistsMock + apiClientMock test helpers

The DRY pass audit (#375) found two inline mock patterns repeated across the
vitest suite: a default empty-playlists mock for $lib/api/playlists (4 exact
copies in menu/card tests) and an api-client spy mock for $lib/api/client
(9 callers split between get-only and full-RESTy shapes — unified into one
helper that always returns all four verb spies).

Mirrors the existing test-utils/mocks/likes.ts and test-utils/mocks/quarantine.ts
convention. Tests with intentionally divergent shapes (AddToPlaylistMenu's
richer createPlaylist payload, PlaylistCard's getPlaylist, route-specific
mocks, events.svelte's specific resolved value) stay inline.

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

web/src/routes/discover/discover.test.ts

@@ -1,6 +1,7 @@
 import { afterEach, beforeEach, describe, expect, test, vi } from 'vitest';
 import { render, screen, fireEvent, waitFor } from '@testing-library/svelte';
 import { mockQuery } from '../../test-utils/query';
+import { apiClientMock } from '../../test-utils/mocks/client';
 import type { LidarrSearchResult } from '$lib/api/types';
 
 // Lidarr search query factory and createRequest are mocked at the module
@@ -18,9 +19,7 @@ vi.mock('$lib/api/requests', () => ({
   createRequest: vi.fn().mockResolvedValue({ id: 'r1' })
 }));
 
-vi.mock('$lib/api/client', () => ({
-  api: { get: vi.fn(), post: vi.fn(), put: vi.fn(), del: vi.fn() }
-}));
+vi.mock('$lib/api/client', () => apiClientMock());
 
 import DiscoverPage from './+page.svelte';
 import { createLidarrSearchQuery } from '$lib/api/lidarr';

web/src/routes/library/albums/page.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, test, vi } from 'vitest';
 import { render, screen } from '@testing-library/svelte';
 import { readable } from 'svelte/store';
 import { emptyLikesMock } from '../../../test-utils/mocks/likes';
+import { apiClientMock } from '../../../test-utils/mocks/client';
 
 vi.mock('$lib/api/albums', () => ({
   createAlbumsAlphaInfiniteQuery: () => readable({
@@ -25,7 +26,7 @@ vi.mock('$lib/api/albums', () => ({
   }),
   ALBUM_PAGE_SIZE: 50
 }));
-vi.mock('$lib/api/client', () => ({ api: { get: vi.fn() } }));
+vi.mock('$lib/api/client', () => apiClientMock());
 vi.mock('$lib/player/store.svelte', () => ({
   enqueueTracks: vi.fn(),
   playQueue: vi.fn()

web/src/routes/library/artists/page.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, test, vi } from 'vitest';
 import { render, screen } from '@testing-library/svelte';
 import { readable } from 'svelte/store';
 import { emptyLikesMock } from '../../../test-utils/mocks/likes';
+import { apiClientMock } from '../../../test-utils/mocks/client';
 
 vi.mock('$lib/api/queries', () => ({
   createArtistsQuery: () => readable({
@@ -20,7 +21,7 @@ vi.mock('$lib/api/queries', () => ({
     fetchNextPage: () => {}
   })
 }));
-vi.mock('$lib/api/client', () => ({ api: { get: vi.fn() } }));
+vi.mock('$lib/api/client', () => apiClientMock());
 vi.mock('$lib/player/store.svelte', () => ({
   playQueue: vi.fn(),
   enqueueTracks: vi.fn()

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

@@ -1,6 +1,7 @@
 import { afterEach, describe, expect, test, vi } from 'vitest';
 import { render, screen, fireEvent } from '@testing-library/svelte';
 import { mockInfiniteQuery } from '../../../test-utils/query';
+import { apiClientMock } from '../../../test-utils/mocks/client';
 import type { ArtistRef, AlbumRef, TrackRef, Page } from '$lib/api/types';
 import { readable } from 'svelte/store';
 import { makeTrack } from '$test-utils/fixtures/track';
@@ -18,7 +19,7 @@ vi.mock('$lib/api/likes', () => ({
   unlikeEntity: vi.fn()
 }));
 
-vi.mock('$lib/api/client', () => ({ api: { get: vi.fn() } }));
+vi.mock('$lib/api/client', () => apiClientMock());
 vi.mock('$lib/player/store.svelte', () => ({
   playQueue: vi.fn(), enqueueTrack: vi.fn(), enqueueTracks: vi.fn()
 }));

web/src/routes/requests/requests.test.ts

@@ -1,6 +1,7 @@
 import { afterEach, describe, expect, test, vi } from 'vitest';
 import { render, screen, fireEvent, waitFor } from '@testing-library/svelte';
 import { mockQuery } from '../../test-utils/query';
+import { apiClientMock } from '../../test-utils/mocks/client';
 import type { LidarrRequest } from '$lib/api/types';
 
 // Capture invalidateQueries on the mocked QueryClient so the cancel test can
@@ -23,9 +24,7 @@ vi.mock('$lib/api/queries', () => ({
   }
 }));
 
-vi.mock('$lib/api/client', () => ({
-  api: { get: vi.fn(), post: vi.fn(), put: vi.fn(), del: vi.fn() }
-}));
+vi.mock('$lib/api/client', () => apiClientMock());
 
 import RequestsPage from './+page.svelte';
 import { createMyRequestsQuery, cancelRequest } from '$lib/api/requests';

web/src/routes/search/albums/albums.test.ts

@@ -2,6 +2,7 @@ import { afterEach, describe, expect, test, vi } from 'vitest';
 import { render, screen, fireEvent } from '@testing-library/svelte';
 import { mockInfiniteQuery } from '../../../test-utils/query';
 import { emptyLikesMock } from '../../../test-utils/mocks/likes';
+import { apiClientMock } from '../../../test-utils/mocks/client';
 import { pageUrlModule } from '$test-utils/mocks/appState';
 import type { AlbumRef, Page } from '$lib/api/types';
 
@@ -13,9 +14,7 @@ vi.mock('$lib/api/queries', () => ({
   createSearchAlbumsInfiniteQuery: vi.fn()
 }));
 
-vi.mock('$lib/api/client', () => ({
-  api: { get: vi.fn() }
-}));
+vi.mock('$lib/api/client', () => apiClientMock());
 vi.mock('$lib/player/store.svelte', () => ({
   enqueueTracks: vi.fn()
 }));

web/src/routes/search/search.test.ts

@@ -2,6 +2,7 @@ import { afterEach, describe, expect, test, vi } from 'vitest';
 import { render, screen } from '@testing-library/svelte';
 import { mockQuery } from '../../test-utils/query';
 import { emptyLikesMock } from '../../test-utils/mocks/likes';
+import { apiClientMock } from '../../test-utils/mocks/client';
 import { pageUrlModule } from '$test-utils/mocks/appState';
 import type { ArtistRef, AlbumRef, SearchResponse } from '$lib/api/types';
 import { makeTrack } from '$test-utils/fixtures/track';
@@ -23,9 +24,7 @@ vi.mock('$lib/player/store.svelte', () => ({
   enqueueTracks: vi.fn()
 }));
 
-vi.mock('$lib/api/client', () => ({
-  api: { get: vi.fn() }
-}));
+vi.mock('$lib/api/client', () => apiClientMock());
 
 vi.mock('$lib/api/likes', () => emptyLikesMock());