fix(deploy): proxy /api/ to fastapi in nginx-m1.conf for M3 smoke checks

deploy/nginx-m1.conf

@@ -5,6 +5,19 @@ server {
     index index.html;
 
     # SPA: fall back to index.html for any path
+    # Proxy API calls to the FastAPI backend (M3+)
+    location /api/ {
+        proxy_pass http://fastapi:8000;
+        proxy_http_version 1.1;
+        proxy_set_header Upgrade $http_upgrade;
+        proxy_set_header Connection 'upgrade';
+        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;
+        proxy_cache_bypass $http_upgrade;
+    }
+
     location / {
         try_files $uri $uri/ /index.html;
     }