feat: add runtime policy and observability

docker/nginx.conf

@@ -22,6 +22,12 @@ http {
     listen 80;
     server_name _;
 
+    add_header X-Content-Type-Options "nosniff" always;
+    add_header X-Frame-Options "SAMEORIGIN" always;
+    add_header Referrer-Policy "strict-origin-when-cross-origin" always;
+    add_header Permissions-Policy "camera=(), microphone=(), geolocation=()" always;
+    add_header Content-Security-Policy "default-src 'self'; base-uri 'self'; object-src 'none'; frame-ancestors 'self'; form-action 'self'; img-src 'self' data: blob: https:; font-src 'self' data:; style-src 'self' 'unsafe-inline'; script-src 'self'; connect-src 'self' https:" always;
+
     root /usr/share/nginx/html;
 
     location /api/ {
@@ -44,6 +50,11 @@ http {
       proxy_pass http://imageforge_api;
     }
 
+    # Prometheus should scrape the API container directly on the private network.
+    location = /metrics {
+      return 404;
+    }
+
     # SPA fallback
     location / {
       try_files $uri $uri/ /index.html;