fix: serve the website dist so Coolify answers GET /

Nixpacks built Vite but had no production start command, so Coolify returned Cannot GET /.

Co-authored-by: Cursor <cursoragent@cursor.com>

packages/website/nginx.conf

@@ -0,0 +1,16 @@
+server {
+  listen 80;
+  server_name _;
+  root /usr/share/nginx/html;
+  index index.html;
+
+  location = /healthz {
+    access_log off;
+    add_header Content-Type text/plain;
+    return 200 'ok';
+  }
+
+  location / {
+    try_files $uri $uri/ /index.html;
+  }
+}