feat: add personal playlists and shareable track links

EOF

Co-authored-by: Cursor <cursoragent@cursor.com>

packages/core/src/share.ts

@@ -0,0 +1,4 @@
+/** Public page URL: never includes playback credentials or stream URLs. */
+export function trackShareUrl(server: string, trackId: string): string {
+  return new URL(`/track/${encodeURIComponent(trackId)}`, server).href;
+}