> Asynchronous triggers and HMAC-signed webhook handlers

# Webhook API

Trigger agents from external CI/CD or alert systems without sharing administrative tokens (`internal/http/webhooks.go`).

## Webhook Types

* `POST /v1/webhooks/message` — Ingests inbound channel messages from external webhook providers.
* `POST /v1/webhooks/llm` — Synchronous single-turn LLM completion trigger with HMAC verification.