Pick the music services you use

Songs offered links to all five services. Settings now has "Your music
services": pick the ones you use and songs only show those, with the
main one as the big button. Until someone picks, they still see all of
them. Onboarding sets it to the app you said you listen with.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/api/test/auth.test.ts

@@ -115,3 +115,16 @@ describe('onboarding flag', () => {
     expect(again.onboardedAt).toBe(first.onboardedAt);
   });
 });
+
+describe('music services', () => {
+  it('saves the services you use, without duplicates, and clears them', async () => {
+    const { token, user } = await createUser(app(), 'listener');
+    expect(user.services).toBeNull();
+    const patch = (payload: object) => app().inject({ method: 'PATCH', url: '/me', headers: bearer(token), payload });
+    const saved = (await patch({ services: ['spotify', 'tidal', 'spotify'], preferredService: 'tidal' })).json();
+    expect(saved.services).toEqual(['spotify', 'tidal']);
+    expect(saved.preferredService).toBe('tidal');
+    expect((await patch({ services: ['napster'] })).statusCode).toBe(400);
+    expect((await patch({ services: null })).json().services).toBeNull();
+  });
+});