Configurable hold window before Chirp AI posts a review response

Chirp AI currently posts review responses as soon as the review is detected, leaving no gap for local teams to see the review first. Add a per-account (ideally per-property-group) hold window — e.g. 2, 12, 24, or 48 hours — between review ingestion and the AI reply being published. During the hold, the generated response sits in a pending state where a team member can edit, approve, or replace it; if nobody acts before the window closes, it posts automatically as it does today. Also surface the configured window in the UI so managers know what timing they're on.