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

deploy/export-db.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+# Save the local database to a file you can carry to the server.
+#   deploy/export-db.sh [output-file]
+set -euo pipefail
+cd "$(dirname "$0")/.."
+out="${1:-musicshare-$(date +%Y%m%d-%H%M).dump}"
+docker compose exec -T postgres pg_dump -U musicshare -d musicshare --format=custom --no-owner > "$out"
+echo "Saved $(du -h "$out" | cut -f1) to $out"
+echo
+echo "IMPORTANT: connected services (Plex, Last.fm, Jellyfin...) are encrypted with TOKEN_ENCRYPTION_KEY."
+echo "Put the SAME key in deploy/production.env on the server, or those connections must be redone:"
+grep '^TOKEN_ENCRYPTION_KEY=' apps/api/.env 2>/dev/null | sed 's/=.*/=<copy the value from apps\/api\/.env>/' || true