UpDoc worker

This is a headless cron worker. There are no user-facing pages. The active endpoints are:

• /api/healthz — process liveness (no DB call).
• /api/readyz — readiness, performs a trivial Supabase query.
• /api/cron/process-notifications — notifications outbox dispatcher. Bearer-secured.
• /api/cron/maintain-audit — audit-log partition maintenance. Bearer-secured.
• /api/cron/finalize-expired-shifts — closes stale marketplace postings after roster end. Bearer-secured.