Fix nginx configuration for Portainer deployment

- Remove quotes from Connection header value to fix nginx parsing error
- Simplify Cache-Control header to avoid argument parsing issues
- Clean up embedded nginx config formatting for better compatibility
- Resolves "invalid number of arguments in proxy_set_header directive" error

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

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

docker-compose.yml

@@ -81,34 +81,27 @@ configs:
       events {
           worker_connections 1024;
       }
-
       http {
           upstream frontend {
               server frontend:3000;
           }
-
           upstream backend {
               server backend:8080;
           }
-
           server {
               listen 80;
               client_max_body_size 10M;
-
-              # Frontend routes
               location / {
                   proxy_pass http://frontend;
                   proxy_http_version 1.1;
                   proxy_set_header Upgrade $http_upgrade;
-                  proxy_set_header Connection '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;
               }
-
-              # Backend API routes
               location /api/ {
                   proxy_pass http://backend/api/;
                   proxy_set_header Host $host;
@@ -119,15 +112,11 @@ configs:
                   proxy_send_timeout 60s;
                   proxy_read_timeout 60s;
               }
-
-              # Static image serving
               location /images/ {
                   alias /app/images/;
                   expires 1y;
-                  add_header Cache-Control "public, immutable";
+                  add_header Cache-Control public;
               }
-
-              # Typesense admin interface
               location /typesense/ {
                   proxy_pass http://typesense:8108/;
                   proxy_set_header Host $host;