Do not serve internal strategy paths publicly

.vercelignore does not take effect on this deployment (growth/PLAN.md
returned 200 live after being added to it), so block /.agents/* and
/growth/* with rewrites to a nonexistent path instead.

vercel.json

@@ -251,6 +251,10 @@
       "permanent": true
     }
   ],
+  "rewrites": [
+    { "source": "/.agents/:path*", "destination": "/__internal-only" },
+    { "source": "/growth/:path*", "destination": "/__internal-only" }
+  ],
   "headers": [
     {
       "source": "/(.*)",