Add idle auto-shutdown configuration to deployment

- IDLE_TIMEOUT_MINUTES env var (default 30 min)
- restart: no policy so container stays stopped
- Optional wakeup service for auto-restart
- Document three restart options in readme

deploy/nginx.conf

@@ -0,0 +1,45 @@
+events {
+    worker_connections 1024;
+}
+
+http {
+    upstream streamlit {
+        server streamlit:8080;
+    }
+
+    server {
+        listen 80;
+        server_name _;
+
+        # Remove X-Frame-Options to allow iframe embedding
+        proxy_hide_header X-Frame-Options;
+
+        # Allow embedding from your domain
+        add_header Content-Security-Policy "frame-ancestors 'self' https://kschappell.com https://*.kschappell.com";
+
+        location / {
+            proxy_pass http://streamlit;
+            proxy_http_version 1.1;
+
+            # WebSocket support (required for Streamlit)
+            proxy_set_header Upgrade $http_upgrade;
+            proxy_set_header Connection "upgrade";
+
+            # Standard proxy headers
+            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;
+
+            # Timeouts for long-running connections
+            proxy_read_timeout 86400;
+            proxy_send_timeout 86400;
+        }
+
+        # Health check endpoint
+        location /health {
+            return 200 'ok';
+            add_header Content-Type text/plain;
+        }
+    }
+}