shifting node-3 clock +300s (NTP disabled for the duration)
  node-3 now reports: Wed Apr 22 12:37:13 UTC 2026
alice writes on node-1 (normal clock); waiting for quorum fanout to skewed node-3
settle 15s for skewed-peer convergence
  node-3 (+300s clock) sees marker: 1 (expected >=1)
  node-1 sees marker: 1 (expected >=1)
reverting node-3 clock