Production deploy for musicshare.binarygnome.com

- docker-compose.prod.yml overlay: Caddy with automatic HTTPS on one
  origin (web at /, API at /api incl. websocket), internal-only Postgres/
  Redis/API/web, secure cookies, private-network servers blocked, nightly
  pg_dump backups kept 14 days
- deploy/export-db.sh and import-db.sh to carry a database to the server
  (same TOKEN_ENCRYPTION_KEY required for stored connections)
- Base compose no longer requires apps/api/.env
- README: deployment, Spotify via scrobblers, SMTP settings

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

.gitignore

@@ -6,3 +6,7 @@ dist
 .turbo
 *.tsbuildinfo
 next-env.d.ts
+
+# Production secrets and database backups
+deploy/production.env
+backups/