Unlock everything, add a donation link, credit Last.fm, nudge re-linking

- Every feature is free for everyone (the plan system stays for later);
  remaining limits are abuse guards
- Optional website donation link (NEXT_PUBLIC_DONATION_URL). Not shown in
  the mobile apps, where tips to the developer generally need in-app
  purchase
- Last.fm/ListenBrainz-sourced plays link to the user's profile, as
  Last.fm's API terms require
- Connections track when they last saw activity; a scrobbler silent for
  over a week prompts re-linking Spotify (its link expires every 6 months)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MzFywujuH9TiuXbr9vjoX8

packages/shared/src/services.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { STREAMING_SERVICES, openUrl, searchUrl } from './services';
+import { STREAMING_SERVICES, isQuietScrobbler, openUrl, searchUrl } from './services';
 
 const track = { title: 'Midnight City', artist: 'M83', links: { spotify: 'https://open.spotify.com/track/abc' } };
 
@@ -22,3 +22,21 @@ describe('searchUrl', () => {
     expect(decodeURIComponent(url.href)).toContain('Ünïcode Café & Co');
   });
 });
+
+describe('isQuietScrobbler', () => {
+  const now = new Date('2026-10-04T12:00:00Z').getTime();
+  const conn = (provider: string, daysAgo: number | null) => ({
+    provider,
+    status: 'active',
+    lastActivityAt: daysAgo === null ? null : new Date(now - daysAgo * 86_400_000).toISOString(),
+  });
+  it('flags Last.fm/ListenBrainz that went silent for over a week', () => {
+    expect(isQuietScrobbler(conn('lastfm', 8), now)).toBe(true);
+    expect(isQuietScrobbler(conn('listenbrainz', 30), now)).toBe(true);
+  });
+  it('ignores recent activity, never-active connections, and other providers', () => {
+    expect(isQuietScrobbler(conn('lastfm', 2), now)).toBe(false);
+    expect(isQuietScrobbler(conn('lastfm', null), now)).toBe(false);
+    expect(isQuietScrobbler(conn('spotify', 30), now)).toBe(false);
+  });
+});