feat: resolve chromecast discovery conflict and add CI/CD workflow

- Update Zeroconf to unicast mode to resolve port 5353 conflict with avahi-daemon
- Make API and Streamlit ports configurable via environment variables (defaults: 8055, 8505)
- Add Gitea Actions workflow for automated Docker builds and registry pushes
- Refactor Chromecast discovery to use modern CastBrowser API

docker-compose.yml

@@ -12,8 +12,10 @@ services:
     environment:
       - VIDEOS_DIR=/app/videos
       - CONFIG_DIR=/app/config
+      - API_PORT=8055
+      - STREAMLIT_PORT=8505
     healthcheck:
-      test: ["CMD", "curl", "-f", "http://localhost:8501/_stcore/health"]
+      test: ["CMD", "curl", "-f", "http://localhost:8505/_stcore/health"]
       interval: 30s
       timeout: 10s
       retries: 3