Add CI workflow, admin frontend, Prometheus/Grafana monitoring, Cloudflare cache rules and worker, Nginx config, CONTRIBUTING.md and update docker-compose.yml

infrastructure/nginx/Dockerfile

@@ -0,0 +1,9 @@
+FROM nginx:alpine
+
+COPY nginx.conf /etc/nginx/nginx.conf
+
+# Create directories for HLS and frontend
+RUN mkdir -p /usr/share/nginx/html/hls /usr/share/nginx/html/admin
+
+EXPOSE 80
+CMD ["nginx", "-g", "daemon off;"]