Epic: M22 — Infrastructure (gateway, daemon, scheduler)

[bug-ops]

Motivation

Zeph currently runs as a foreground process. For production deployment and webhook-based channel integrations, it needs an HTTP gateway, daemon supervision, and task scheduling.

Scope

1. HTTP gateway — axum endpoint for webhook ingestion with bearer auth
2. Daemon supervisor — background process with health monitoring
3. Cron scheduler — periodic tasks from config

Issues

• Add HTTP gateway with webhook ingestion and bearer auth #379 Add HTTP gateway with webhook ingestion and bearer auth
• Add daemon supervisor with health monitoring #380 Add daemon supervisor with health monitoring
• Add cron scheduler for periodic tasks #381 Add cron scheduler for periodic tasks