alice writes M1 content=v0-24d19cfab94943848abbcfa05d6525de on node-1
  M1 id=158965a8-3c13-4930-b55f-13db8da888c0
settle 5s for initial replication
alice + bob issue concurrent PUTs (vA=va-f058614856d94a4585a81604190217b8 from alice, vB=vb-a6155d6c2369410dbda17225054c2f2a from bob)
  concurrent PUT results: [(0, {'body': {'access_count': 0, 'confidence': 1.0, 'content': 'va-f058614856d94a4585a81604190217b8', 'created_at': '2026-04-22T21:51:46.284463659+00:00', 'expires_at': '2026-04-29T21:51:46.284463659+00:00', 'id': '158965a8-3c13-4930-b55f-13db8da888c0', 'metadata': {'agent_id': 'ai:alice', 'scenario': '13'}, 'namespace': 'scenario13-contention', 'priority': 5, 'source': 'api', 'tags': [], 'tier': 'mid', 'title': 'm1', 'updated_at': '2026-04-22T21:51:51.795859439+00:00'}, 'http_code': 200}), (0, {'body': {'access_count': 0, 'confidence': 1.0, 'content': 'vb-a6155d6c2369410dbda17225054c2f2a', 'created_at': '2026-04-22T21:51:46.284463659+00:00', 'expires_at': '2026-04-29T21:51:46.284463659+00:00', 'id': '158965a8-3c13-4930-b55f-13db8da888c0', 'metadata': {'agent_id': 'ai:alice', 'scenario': '13'}, 'namespace': 'scenario13-contention', 'priority': 5, 'source': 'api', 'tags': [], 'tier': 'mid', 'title': 'm1', 'updated_at': '2026-04-22T21:51:51.706297403+00:00'}, 'http_code': 200})]
settle 10s for quorum convergence
  node-1 sees content=va-f058614856d94a4585a81604190217b8
  node-2 sees content=va-f058614856d94a4585a81604190217b8
  node-3 sees content=va-f058614856d94a4585a81604190217b8
  node-4 sees content=va-f058614856d94a4585a81604190217b8