Add /api/status/ for quick inspection of database backend, object counts, latest
backup run, and latest scheduler activity. Link it from the API index and reuse
schedule serialization between host summaries and status output.
Cover the endpoint with a focused API test and document the new status URL.
Expose lightweight Django JSON endpoints for hosts, snapshots, and backup runs
using the existing admin/staff authentication boundary. Include filters for
snapshot and run inspection, return resolved snapshot base metadata, and document
the new /api/ entrypoint.
Add endpoint tests for authentication, host summaries, snapshot lineage payloads,
and run filtering.
