[scenario-18 hermes] alice writes A on node-1
[scenario-18 hermes] bob writes B on node-2
[scenario-18 hermes] settle 15s for fanout + index rebuild
[scenario-18 hermes] charlie queries on node-3 with semantically-related prompt
[scenario-18 hermes]   charlie sees alice's memory: 0 (expected >=1)
[scenario-18 hermes]   charlie sees bob's memory: 0 (expected >=1)