feat: add admin login page and authentication API

- Created a new login page for admin access at frontend/admin/login/index.html.
- Implemented form submission with error handling for login credentials.
- Updated frontend/index.html to mute the video player and removed unnecessary Alpine.js data binding.
- Enhanced manifest URL resolution in frontend/src/main.ts to include cache-busting parameters.
- Modified vite.config.ts to include the new admin login page in the build process.
- Updated nginx.conf to handle admin login routing, authentication, and API proxying for admin actions.

docker-compose.prod.yml

@@ -30,6 +30,8 @@ services:
       - "${CHAT_PORT:-3000}:3000"
     volumes:
       - ./data/chat:/app:rw
+      - ./data/playlist:/app/playlist:rw
+      - ./data/media:/app/media:rw
     networks:
       - linearvoid-net
     depends_on: