ci: use PAT for release-please to trigger CI on release PRs

GITHUB_TOKEN events don't trigger workflows on PRs they create,
so CI checks never run on release-please PRs. Switch to a PAT
stored as RELEASE_PLEASE_TOKEN secret.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: jdiegosierra

.github/workflows/release-please.yml

@@ -5,10 +5,6 @@ on:
     branches:
       - main
 
-permissions:
-  contents: write
-  pull-requests: write
-
 jobs:
   release-please:
     name: Release Please
@@ -19,7 +15,7 @@ jobs:
         id: release
         uses: googleapis/release-please-action@v4
         with:
-          token: ${{ secrets.GITHUB_TOKEN }}
+          token: ${{ secrets.RELEASE_PLEASE_TOKEN }}
 
       - name: Update floating major tag
         if: ${{ steps.release.outputs.release_created }}