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/Dockerfile

@@ -14,6 +14,9 @@ RUN npm prune --production
 FROM node:20-alpine AS production
 WORKDIR /app
 
+# wget is needed for Docker/Portainer health checks
+RUN apk add --no-cache wget
+
 COPY --from=builder /app/package.json ./package.json
 COPY --from=builder /app/package-lock.json ./package-lock.json
 COPY --from=builder /app/dist ./dist
@@ -21,5 +24,8 @@ COPY --from=builder /app/node_modules ./node_modules
 
 EXPOSE 4000
 
-# Run TypeORM migrations on startup, then start the API
-CMD ["sh", "-c", "npx typeorm migration:run -d dist/database/ormconfig.js 2>/dev/null; export NODE_OPTIONS='--max-old-space-size=1024' && npm run start:prod"]
+ENV NODE_OPTIONS="--max-old-space-size=1024"
+
+# Run TypeORM migrations on startup, then start the API.
+# Migration errors are logged (not suppressed) so failed deploys are visible.
+CMD ["sh", "-c", "echo 'Running database migrations...' && npx typeorm migration:run -d dist/database/ormconfig.js && echo 'Migrations complete.' && npm run start:prod"]