Improve jobs control plane and status API

[kraftaa]

Summary

• Add control-plane schema and CLI for scheduled sync jobs (init-jobs, add-job, worker, force-job).
• Add status API with JSON + HTML views, filters, auto-refresh, and /health.
• Record job runs with severity/metrics; optional DQ hook via RUSTREAM_DQ_CMD.
• Support per-job timeout and max_concurrent flags; backfill schema on startup.

Testing

• cargo test
• Manual: init-jobs, add-job, worker, status-api; verified /jobs, /logs, /health endpoints.