ci(release): pass the minted GitHub App token to release-please (#342)

The create-github-app-token step output was never referenced; release-please
still used the RELEASE_PLEASE_TOKEN PAT. Use the app token so release PRs are
opened by the app and trigger CI; the PAT secret can be retired.

Closes #338


Claude-Session: https://claude.ai/code/session_01N4pngRiBqeb1xiseKXNLG6

Co-authored-by: Claude <noreply@anthropic.com>

Author: gabrielfrasantos

.github/workflows/release-please.yml

@@ -26,4 +26,4 @@ jobs:
       - uses: googleapis/release-please-action@45996ed1f6d02564a971a2fa1b5860e934307cf7 # v5.0.0
         id: release
         with:
-          token: ${{ secrets.RELEASE_PLEASE_TOKEN }}
+          token: ${{ steps.token.outputs.token }}