Add nginx reverse proxy and environment configuration

- Add nginx.conf for proxying API requests to backend
- Update frontend Dockerfile for production build with nginx
- Move hardcoded values to .env variables in docker-compose.yml
- Add .env.example template for configuration

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

nginx/nginx.conf

@@ -0,0 +1,90 @@
+upstream backend {
+    server backend:8000;
+}
+
+server {
+    listen 80;
+    server_name localhost;
+
+    # Frontend static files
+    location / {
+        root /usr/share/nginx/html;
+        index index.html;
+        try_files $uri $uri/ /index.html;
+    }
+
+    # Downloader API
+    location /api/downloader {
+        proxy_pass http://backend;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+    }
+
+    # Openings API
+    location /api/openings {
+        proxy_pass http://backend;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+    }
+
+    # Backgrounds API
+    location /api/backgrounds {
+        proxy_pass http://backend;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+    }
+
+    # Core API - strip /api prefix
+    location /api/ {
+        proxy_pass http://backend/;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+    }
+
+    # Videos endpoint
+    location /videos {
+        proxy_pass http://backend;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+    }
+
+    # Download endpoint
+    location /download {
+        proxy_pass http://backend;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+    }
+
+    # Health check
+    location /health {
+        proxy_pass http://backend;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+    }
+
+    # Increase max body size for video uploads
+    client_max_body_size 500M;
+
+    # Timeouts for long video generation
+    proxy_connect_timeout 300s;
+    proxy_send_timeout 300s;
+    proxy_read_timeout 300s;
+}