feat(web): add TanStack Query helpers for library endpoints

qk.{artists,artist,album} key generators and create*Query wrappers
with shared page size, sort-aware keys, and infinite-query plumbing
for /api/artists.

web/src/lib/api/queries.test.ts

@@ -0,0 +1,17 @@
+import { describe, expect, test } from 'vitest';
+import { qk } from './queries';
+
+describe('qk key generators', () => {
+  test('artists key includes sort discriminator', () => {
+    expect(qk.artists('alpha')).toEqual(['artists', { sort: 'alpha' }]);
+    expect(qk.artists('newest')).toEqual(['artists', { sort: 'newest' }]);
+  });
+
+  test('artist key tuple', () => {
+    expect(qk.artist('abc')).toEqual(['artist', 'abc']);
+  });
+
+  test('album key tuple', () => {
+    expect(qk.album('xyz')).toEqual(['album', 'xyz']);
+  });
+});