CRUD + actions for cron jobs on the existing API server (port 8642):
GET /api/jobs — list jobs
POST /api/jobs — create job
GET /api/jobs/{id} — get job
PATCH /api/jobs/{id} — update job
DELETE /api/jobs/{id} — delete job
POST /api/jobs/{id}/pause — pause job
POST /api/jobs/{id}/resume — resume job
POST /api/jobs/{id}/run — trigger immediate run
All endpoints use existing API_SERVER_KEY auth. Job ID format
validated (12 hex chars). Logic ported from PR #2111 by nock4,
adapted from FastAPI to aiohttp on the existing API server.