chore(ops): desliga deploys automáticos do Git no Vercel

git.deploymentEnabled: false impede que pushes e PRs disparem deployments;
produção continua só via ci.yml → vercel deploy --prebuilt --prod.

vercel.json

@@ -1,5 +1,8 @@
 {
   "$schema": "https://openapi.vercel.sh/vercel.json",
   "regions": ["gru1"],
+  "git": {
+    "deploymentEnabled": false
+  },
   "ignoreCommand": "bash scripts/vercel-ignore-build.sh"
 }