Enhance Docker and backend configurations for improved deployment

- Updated docker-compose.yml to include environment variable support for services, enhancing flexibility in configuration.
- Refactored Dockerfile to utilize build arguments for VITE environment variables, allowing for better customization during builds.
- Improved Nginx configuration to handle larger video uploads by increasing client_max_body_size to 5GB.
- Enhanced backend Dockerfile to include wget for health checks and improved startup logging for database migrations.
- Added validation for critical environment variables in the backend to ensure necessary configurations are present before application startup.
- Updated content streaming logic to support direct HLS URL construction, improving streaming reliability and user experience.
- Refactored various components and services to streamline access checks and improve error handling during content playback.

backend/.dockerignore

@@ -0,0 +1,13 @@
+node_modules
+dist
+.git
+.env
+.env.*
+npm-debug.log*
+.DS_Store
+.vscode
+.idea
+.cursor
+*.swp
+*.swo
+*~