feat(social): add friends, private chats, inbox and music sharing

packages/core/src/social.test.ts

@@ -0,0 +1,11 @@
+import { describe, expect, it } from 'vitest';
+import { attachmentPath } from './social';
+
+describe('music attachments', () => {
+  it('creates only internal catalog links and escapes identifiers', () => {
+    expect(attachmentPath({ attachment_kind: 'track', attachment_id: 'a/b?sig=secret' })).toBe('/track/a%2Fb%3Fsig%3Dsecret');
+    expect(attachmentPath({ attachment_kind: 'playlist', attachment_id: 'a/b' })).toBe('/shared/playlist/a%2Fb');
+    expect(attachmentPath({ attachment_kind: 'none' })).toBeNull();
+    expect(attachmentPath({ attachment_kind: 'track' })).toBeNull();
+  });
+});