feat: M3 peer gossip protocol
Refs #1
- peers table (peer_id, addr, cursor, last_handshake)
- watch serves HTTP API: GET /v1/ping (knowledge vector),
GET /v1/log?node=&after= (cursor-paged pull), POST /v1/obs/batch
- anti-entropy sweep (Run): ping, pull what we lack, push own obs;
echo suppressed by node_id ownership; reconcile-on-pull
- config via KNOX_PEERS / KNOX_PEER_ADDR; knox gossip status
- db: GossipObservation wire type, PushObservations, ObservationsAfter,
KnowledgeVector, peer upsert/list
- integration tests: bidirectional convergence + idempotency
david
8c054094a1