alice writes 5 rows into scenario38-src-aa7bab
settle 4s for pre-export replication
alice exports on node-1 (endpoint has no namespace filter; filter client-side)
  export returned HTTP 200, total_rows=232
  rewrote 5 memories from scenario38-src-aa7bab -> scenario38-dst-aa7bab
bob imports the payload into scenario38-dst-aa7bab on node-2
  import returned HTTP 200
settle 6s for import + fanout
verify row counts match on destination
  scenario38-dst-aa7bab has 5 rows (expected 5)
  markers preserved in destination: 5/5