feat(web): add home/albums/artists API clients for M6a

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/src/lib/api/artists.ts

@@ -0,0 +1,16 @@
+import { createQuery } from '@tanstack/svelte-query';
+import { api } from './client';
+import { qk } from './queries';
+import type { TrackRef } from './types';
+
+export async function listArtistTracks(artistId: string): Promise<TrackRef[]> {
+  return api.get<TrackRef[]>(`/api/artists/${artistId}/tracks`);
+}
+
+export function createArtistTracksQuery(artistId: string) {
+  return createQuery({
+    queryKey: qk.artistTracks(artistId),
+    queryFn: () => listArtistTracks(artistId),
+    enabled: artistId.length > 0
+  });
+}