chore(gha): disable nightly trigger and remove pr-labeler workflow

Author: cx-luis-ventuzelos

.github/workflows/nightly.yml

@@ -1,9 +1,10 @@
 name: Nightly Release
 
 on:
-  push:
-    branches:
-      - main
+  workflow_dispatch: # push disabled — re-enable when nightly is ready
+  # push:
+  #   branches:
+  #     - main
 
 permissions:
   contents: read