docs: restore PAT-as-temporary-mechanism note and GitHub App production path

Co-authored-by: craxal <3473026+craxal@users.noreply.github.com>

Author: Copilot

.github/workflows/stale-issue-cleanup.yml

@@ -27,6 +27,15 @@ name: Stale Issue Cleanup
 #    - `project`   — update the Resolution field on the org-level project
 #    - `repo`      — comment on and close issues
 #
+#    PATs are a temporary onboarding mechanism. For production, replace with a GitHub App
+#    token to avoid manual renewal:
+#    - Register a "Storage Explorer Automation" GitHub App in the microsoft org
+#    - Grant it `members:read` and `projects:write` permissions
+#    - Install it on this repo
+#    - Use `actions/create-github-app-token` to generate tokens at runtime
+#    Note: a GitHub App cannot hold a Copilot seat, so COPILOT_TOKEN will always require
+#    a personal Fine-Grained PAT.
+#
 # # Install Step Note
 #
 # The "Install Copilot CLI" step downloads from gh.io/copilot-install, which is a public