phase A: each agent writes 10 memories via MCP
  ai:alice on 142.93.181.41
  ai:bob on 134.209.172.71
  ai:charlie on 142.93.79.13
settle 15s for W=2/N=4 convergence
phase B: each agent counts rows in the OTHER two namespaces
  ai:alice recalled 20 rows from the other two namespaces
  ai:bob recalled 20 rows from the other two namespaces
  ai:charlie recalled 20 rows from the other two namespaces
phase C: cross-cluster identity check on node-4
  ns=scenario1-ai:alice count=10 wrong_agent_id=0
  ns=scenario1-ai:bob count=10 wrong_agent_id=0
  ns=scenario1-ai:charlie count=10 wrong_agent_id=0