[callumreid]

• Retry Homebrew PR lookup/create/update only for HTTP 403 with confirmed exhausted primary quota or HTTP 429 with valid retry timing. Bound retries to three attempts and a monotonic 3605-second budget; limit only the Homebrew job to 70 minutes.
• Reconcile the exact release branch against main before retries, including lost create responses and concurrent creators. Other permission errors fail immediately. Preserve inherited runtime authentication and existing tag, build, release, asset and formula behavior; no version bump.
• Validation: 86 automation tests pass, including 19 publisher cases covering timing bounds, invalid headers, primary/secondary quota, lost responses, concurrent 422, idempotency and workflow boundaries. Ruff, actionlint and whitespace checks pass; the response parser also passed a read-only GitHub lookup.
• The candidate helper has performed no live writes. Local quota/reset cases use mocks; exact-head GitHub CI and normal independent approval remain required.