* ci: drop --delete-branch from reconcile auto-merge call
The reconcile job runs without a git checkout, so gh pr merge --delete-branch
fails with 'not a git repository' before enabling auto-merge. Auto-merge
itself needs no local git state; branch cleanup is already handled by the
PR-creating workflows.
* ci: checkout repo in bot auto-merge workflows
gh pr merge fails with 'not a git repository' when no checkout is present,
which prevented the reconcile job from enabling auto-merge. Restore the
checkout the previous approval workflow relied on.