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.

Dockerfile

@@ -12,20 +12,20 @@ RUN npm ci
 # Copy source code
 COPY . .
 
-# Clear VITE_NOSTR_RELAYS so the app auto-detects the relay
-# via the /relay nginx proxy at runtime (instead of hardcoding localhost)
-ENV VITE_NOSTR_RELAYS=""
+# ── Build-time configuration via ARGs ────────────────────────
+# These are baked into the static JS bundle at build time.
+# Override them with docker-compose build.args or --build-arg.
+ARG VITE_NOSTR_RELAYS=""
+ARG VITE_USE_MOCK_DATA=false
+ARG VITE_CONTENT_ORIGIN=
+ARG VITE_INDEEHUB_API_URL=/api
+ARG VITE_INDEEHUB_CDN_URL=/storage
 
-# Enable mock data mode as default — set to false to use the backend API
-ENV VITE_USE_MOCK_DATA=true
-
-# Content origin must match the seeder's ORIGIN so that relay queries find
-# the seeded data, regardless of how users access the app in their browser
-ENV VITE_CONTENT_ORIGIN=http://localhost:7777
-
-# IndeeHub self-hosted backend API (via nginx /api proxy)
-ENV VITE_INDEEHUB_API_URL=/api
-ENV VITE_INDEEHUB_CDN_URL=/storage
+ENV VITE_NOSTR_RELAYS=${VITE_NOSTR_RELAYS}
+ENV VITE_USE_MOCK_DATA=${VITE_USE_MOCK_DATA}
+ENV VITE_CONTENT_ORIGIN=${VITE_CONTENT_ORIGIN}
+ENV VITE_INDEEHUB_API_URL=${VITE_INDEEHUB_API_URL}
+ENV VITE_INDEEHUB_CDN_URL=${VITE_INDEEHUB_CDN_URL}
 
 # Build the application
 RUN npm run build