alice writes M1 content=v0-1c0ce7e1c33545cb8030df9434481bea on node-1
  M1 id=556ab315-cb62-4c6f-920a-8799c854c03e
settle 5s for initial replication
alice + bob issue concurrent PUTs (vA=va-f025439b010b42edb906e39bb95d703d from alice, vB=vb-c7f212508f4c401a97ec474ad330806d from bob)
  concurrent PUT results: [(0, {'body': {'access_count': 0, 'confidence': 1.0, 'content': 'va-f025439b010b42edb906e39bb95d703d', 'created_at': '2026-04-24T13:43:24.772433878+00:00', 'expires_at': '2026-05-01T13:43:24.772433878+00:00', 'id': '556ab315-cb62-4c6f-920a-8799c854c03e', 'metadata': {'agent_id': 'ai:alice', 'scenario': '13'}, 'namespace': 'scenario13-contention', 'priority': 5, 'source': 'api', 'tags': [], 'tier': 'mid', 'title': 'm1', 'updated_at': '2026-04-24T13:43:29.916882052+00:00'}, 'http_code': 200}), (0, {'body': {'access_count': 0, 'confidence': 1.0, 'content': 'vb-c7f212508f4c401a97ec474ad330806d', 'created_at': '2026-04-24T13:43:24.772433878+00:00', 'expires_at': '2026-05-01T13:43:24.772433878+00:00', 'id': '556ab315-cb62-4c6f-920a-8799c854c03e', 'metadata': {'agent_id': 'ai:alice', 'scenario': '13'}, 'namespace': 'scenario13-contention', 'priority': 5, 'source': 'api', 'tags': [], 'tier': 'mid', 'title': 'm1', 'updated_at': '2026-04-24T13:43:29.916880989+00:00'}, 'http_code': 200})]
settle 10s for quorum convergence
  node-1 sees content=va-f025439b010b42edb906e39bb95d703d
  node-2 sees content=va-f025439b010b42edb906e39bb95d703d
  node-3 sees content=va-f025439b010b42edb906e39bb95d703d
  node-4 sees content=va-f025439b010b42edb906e39bb95d703d