alice writes M1 content=v0-341fd0ba3a774e3b97c4eddda153507e on node-1
  M1 id=96cd3044-a503-42d0-833b-776c5e76765d
settle 5s for initial replication
alice + bob issue concurrent PUTs (vA=va-4f3f9fd3bf974643916a8970ac0ce3bd from alice, vB=vb-6f9680dfaf0c4233bab0bedc4055eeca from bob)
  concurrent PUT results: [(0, {'body': {'access_count': 0, 'confidence': 1.0, 'content': 'va-4f3f9fd3bf974643916a8970ac0ce3bd', 'created_at': '2026-04-24T14:05:13.824352585+00:00', 'expires_at': '2026-05-01T14:05:13.824352585+00:00', 'id': '96cd3044-a503-42d0-833b-776c5e76765d', 'metadata': {'agent_id': 'ai:alice', 'scenario': '13'}, 'namespace': 'scenario13-contention', 'priority': 5, 'source': 'api', 'tags': [], 'tier': 'mid', 'title': 'm1', 'updated_at': '2026-04-24T14:05:18.978376576+00:00'}, 'http_code': 200}), (0, {'body': {'access_count': 0, 'confidence': 1.0, 'content': 'vb-6f9680dfaf0c4233bab0bedc4055eeca', 'created_at': '2026-04-24T14:05:13.824352585+00:00', 'expires_at': '2026-05-01T14:05:13.824352585+00:00', 'id': '96cd3044-a503-42d0-833b-776c5e76765d', 'metadata': {'agent_id': 'ai:alice', 'scenario': '13'}, 'namespace': 'scenario13-contention', 'priority': 5, 'source': 'api', 'tags': [], 'tier': 'mid', 'title': 'm1', 'updated_at': '2026-04-24T14:05:18.953715116+00:00'}, 'http_code': 200})]
settle 10s for quorum convergence
  node-1 sees content=va-4f3f9fd3bf974643916a8970ac0ce3bd
  node-2 sees content=va-4f3f9fd3bf974643916a8970ac0ce3bd
  node-3 sees content=va-4f3f9fd3bf974643916a8970ac0ce3bd
  node-4 sees content=va-4f3f9fd3bf974643916a8970ac0ce3bd