alice writes M1 content=v0-ad1d111ed9a14f8a8363bba440ad2bb9 on node-1
  M1 id=cc90278a-214d-4b38-8865-72db5c7687c7
settle 5s for initial replication
alice + bob issue concurrent PUTs (vA=va-43ae388dbdf349da8039d28dbcf431b2 from alice, vB=vb-6198030747a14465a3bc1f4990fa007d from bob)
  concurrent PUT results: [(0, {'body': {'access_count': 0, 'confidence': 1.0, 'content': 'va-43ae388dbdf349da8039d28dbcf431b2', 'created_at': '2026-04-22T22:00:33.732446122+00:00', 'expires_at': '2026-04-29T22:00:33.732446122+00:00', 'id': 'cc90278a-214d-4b38-8865-72db5c7687c7', 'metadata': {'agent_id': 'ai:alice', 'scenario': '13'}, 'namespace': 'scenario13-contention', 'priority': 5, 'source': 'api', 'tags': [], 'tier': 'mid', 'title': 'm1', 'updated_at': '2026-04-22T22:00:39.974691133+00:00'}, 'http_code': 200}), (0, {'body': {'access_count': 0, 'confidence': 1.0, 'content': 'vb-6198030747a14465a3bc1f4990fa007d', 'created_at': '2026-04-22T22:00:33.732446122+00:00', 'expires_at': '2026-04-29T22:00:33.732446122+00:00', 'id': 'cc90278a-214d-4b38-8865-72db5c7687c7', 'metadata': {'agent_id': 'ai:alice', 'scenario': '13'}, 'namespace': 'scenario13-contention', 'priority': 5, 'source': 'api', 'tags': [], 'tier': 'mid', 'title': 'm1', 'updated_at': '2026-04-22T22:00:40.810796233+00:00'}, 'http_code': 200})]
settle 10s for quorum convergence
  node-1 sees content=vb-6198030747a14465a3bc1f4990fa007d
  node-2 sees content=vb-6198030747a14465a3bc1f4990fa007d
  node-3 sees content=vb-6198030747a14465a3bc1f4990fa007d
  node-4 sees content=vb-6198030747a14465a3bc1f4990fa007d