Queue a failed callback notification for another delivery cycle

Only the signed-in owner can retry a failed callback notification to the current configured receiver. An enabled callback is required. Retry queues a new bounded delivery cycle; it never reruns the job or changes execution_unknown. Event and delivery IDs stay stable; verify the signature and deduplicate X-ActionDock-Delivery. Delivery is at least once, and polling remains available. Agent API keys and MCP tools cannot retry notifications. Requires the owner session and same-origin Origin header. HTTP 202 confirms durable queueing, not receipt by the receiver. Automatic failure retries stop after eight attempts per cycle; startup recovery may repeat an interrupted attempt. attempts resets to zero while the previous HTTP/error result remains until the next result. The original envelope is sent using the current callback URL and secret. Settings changes do not cancel an already-sent notification.