- Implement Fernet encryption for configuration URLs to protect sensitive user settings
- Add CONFIG_SECRET_KEY environment variable for key derivation
- Add server-side /api/config/encode endpoint for secure config token generation
- Add CSRF token generation and validation for all admin POST routes
- Auto-inject CSRF tokens into admin forms and AJAX requests via JavaScript
- Update frontend to use async server encoding instead of client-side Base64
- Add localStorage fallback for config restoration on /configure pages
- Maintain backward compatibility with existing Base64-encoded URLs
- Log warning at startup if CONFIG_SECRET_KEY is not configured
- Convert debug logs to trace level in TorrentSmartContainer for reduced noise
