Clean up legacy env vars, print a warning log if running web_server directly

Dockerfile

@@ -81,8 +81,6 @@ HEALTHCHECK --interval=30s --timeout=10s --start-period=60s --retries=3 \
 # Set environment variables
 ENV PYTHONPATH=/app
 ENV PYTHONUNBUFFERED=1
-ENV FLASK_APP=web_server.py
-ENV FLASK_ENV=production
 ENV DATABASE_PATH=/app/data/music_library.db
 ENV PUID=1000
 ENV PGID=1000

docker-compose.yml

@@ -14,7 +14,6 @@ services:
       - PGID=1000
       - UMASK=022
       # Web server configuration
-      - FLASK_ENV=production
       - PYTHONPATH=/app
       # Optional: Configure through environment variables
       - SOULSYNC_CONFIG_PATH=/app/config/config.json

web_server.py

@@ -54308,5 +54308,6 @@ def start_runtime_services():
 if __name__ == '__main__':
     print("Starting SoulSync Web UI Server...")
     print("Open your browser and navigate to http://127.0.0.1:8008")
+    print("Note: direct `python web_server.py` startup is a legacy fallback; use Gunicorn for production.")
     start_runtime_services()
     socketio.run(app, host='0.0.0.0', port=8008, debug=False, allow_unsafe_werkzeug=True)