alice writes M1 content=v0-1332f5cd97984043a369b02c59ae0f44 on node-1
  M1 id=aa289b84-4e8b-4b4e-8478-bdb394211833
settle 5s for initial replication
alice + bob issue concurrent PUTs (vA=va-300d1affdebc4ec89d501fe00249be69 from alice, vB=vb-166eeb5e6fc14b3e80d3bb3b29b22642 from bob)
  concurrent PUT results: [(0, {'body': {'access_count': 0, 'confidence': 1.0, 'content': 'va-300d1affdebc4ec89d501fe00249be69', 'created_at': '2026-05-02T18:20:31.320403073+00:00', 'expires_at': '2026-05-09T18:20:31.320403073+00:00', 'id': 'aa289b84-4e8b-4b4e-8478-bdb394211833', 'metadata': {'agent_id': 'ai:alice', 'scenario': '13'}, 'namespace': 'scenario13-contention', 'priority': 5, 'source': 'api', 'tags': [], 'tier': 'mid', 'title': 'm1', 'updated_at': '2026-05-02T18:20:36.994952387+00:00'}, 'http_code': 200}), (0, {'body': {'access_count': 0, 'confidence': 1.0, 'content': 'vb-166eeb5e6fc14b3e80d3bb3b29b22642', 'created_at': '2026-05-02T18:20:31.320403073+00:00', 'expires_at': '2026-05-09T18:20:31.320403073+00:00', 'id': 'aa289b84-4e8b-4b4e-8478-bdb394211833', 'metadata': {'agent_id': 'ai:alice', 'scenario': '13'}, 'namespace': 'scenario13-contention', 'priority': 5, 'source': 'api', 'tags': [], 'tier': 'mid', 'title': 'm1', 'updated_at': '2026-05-02T18:20:37.698155826+00:00'}, 'http_code': 200})]
settle 10s for quorum convergence
  node-1 sees content=vb-166eeb5e6fc14b3e80d3bb3b29b22642
  node-2 sees content=vb-166eeb5e6fc14b3e80d3bb3b29b22642
  node-3 sees content=vb-166eeb5e6fc14b3e80d3bb3b29b22642
  node-4 sees content=vb-166eeb5e6fc14b3e80d3bb3b29b22642