Adopt canonical apply-repo-settings stub; delete diverged fork (org std .github#984)

[don-petry]

Part of petry-projects/.github#984 (fleet standardization of the branch-policy compliance self-heal; rollout tracked in petry-projects/.github#989).

Work:

1. Vendor the canonical thin caller stub standards/workflows/apply-repo-settings.yml from petry-projects/.github verbatim to .github/workflows/apply-repo-settings.yml, pinned to this repo's ring channel per standards/canary-rings.json (this repo: see registry entry apply-repo-settings).
2. Delete the diverged local fork: scripts/apply-repo-settings.sh (orphan copy, no workflow).

BLOCKED until the apply-repo-settings/v1-* channel tags exist (petry-projects/.github#989 step 1) — a stub pinned to a nonexistent tag fails at startup. Do not add the dev-lead label before that lands.