Add unit and integration test suites

- Shared: link building, feed ordering, input schemas, API client
- API unit: track matching, private-address blocking, token crypto,
  plan expiry, provider response parsing
- API integration against Postgres and Redis: auth, follows and pins,
  now-playing state, webhooks, OAuth return URLs, realtime, rate limits
- Tests use a dedicated *_test database and Redis DB, and refuse to wipe
  anything else; fetch is stubbed so they never hit the network
- Pin Node to 22.13+ (.nvmrc), which Vite's native bindings require

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

packages/shared/src/services.test.ts

@@ -0,0 +1,24 @@
+import { describe, expect, it } from 'vitest';
+import { STREAMING_SERVICES, openUrl, searchUrl } from './services';
+
+const track = { title: 'Midnight City', artist: 'M83', links: { spotify: 'https://open.spotify.com/track/abc' } };
+
+describe('openUrl', () => {
+  it('uses the direct link when the service has one', () => {
+    expect(openUrl(track, 'spotify')).toEqual({ url: 'https://open.spotify.com/track/abc', exact: true });
+  });
+
+  it('falls back to a search on that service', () => {
+    const result = openUrl(track, 'apple_music');
+    expect(result.exact).toBe(false);
+    expect(result.url).toBe('https://music.apple.com/search?term=M83%20Midnight%20City');
+  });
+});
+
+describe('searchUrl', () => {
+  it.each(STREAMING_SERVICES)('builds an https URL for %s with the query encoded', (service) => {
+    const url = new URL(searchUrl(service, 'Café & Co', 'Ünïcode'));
+    expect(url.protocol).toBe('https:');
+    expect(decodeURIComponent(url.href)).toContain('Ünïcode Café & Co');
+  });
+});