GTM API / Retry webhook delivery

Manually re-arm a webhook delivery row: flips status to pending, sets scheduled_at=now(), clears cancel_reason. retry_count stays (it counts executed attempts, a re-arm is not one). error_message is preserved (cleared only on the next successful terminal outcome). Allowed from every state but in_progress (409 lease_in_progress), cancelled included whatever the reason; rejected on a soft-deleted / disabled parent webhook (422). Many rows at once: replay_webhook on the parent, paced. Pass expected_status for a CAS write (409 on mismatch). Re-delivers to the integrator; state-changing. Contract: - MCP tool retry_webhook_log, registry package mcp.orchestration/webhook_logs, mount orchestration.webhooks. - Operation action, response envelope action. - Flags: dangerous: the MCP layer gates it behind a preview/commit token, and the effect cannot be undone through this API.