New POST /swarm/heartbeat on the swarm controller. Workers post every
~30s with the output of executor.status(); the master bumps
SwarmHost.last_heartbeat and re-upserts each DeckyShard with a fresh
DeckyConfig snapshot and runtime-derived state (running/degraded).
Security: CA-signed mTLS alone is not sufficient — a decommissioned
worker's still-valid cert could resurrect ghost shards. The endpoint
extracts the presented peer cert (primary: scope["extensions"]["tls"],
fallback: transport.get_extra_info("ssl_object")) and SHA-256-pins it
to the SwarmHost.client_cert_fingerprint stored for the claimed
host_uuid. Extraction is factored into _extract_peer_fingerprint so
tests can exercise both uvicorn scope shapes and the both-unavailable
fail-closed path without mocking uvicorn's TLS pipeline.
Adds get_swarm_host_by_fingerprint to the repo interface (SQLModel
impl reuses the indexed client_cert_fingerprint column).
anti
148e51011c