phase A: each agent writes 10 memories via MCP
  ai:alice on 165.227.212.172
  ai:bob on 134.209.45.98
  ai:charlie on 138.197.125.229
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