ci(release): allow manual dispatch of Release Please

Re-running a previous workflow run replays that run's original context, so a secret rotated afterwards is never picked up. A manual trigger gives a fresh run without needing a new commit on main.

- Add workflow_dispatch to the Release Please workflow
- Remove the temporary token diagnostic workflow

Author: Alberto-Codes

.github/workflows/release-please.yml

@@ -4,6 +4,10 @@ on:
   push:
     branches:
       - main
+  # Lets a maintainer re-run the release after fixing something outside the
+  # repo (a rotated RELEASE_PLEASE_TOKEN, for example). Re-running a previous
+  # run replays that run's original context, so it cannot pick up a new secret.
+  workflow_dispatch:
 
 permissions:
   contents: write