GATE A: id before=tfb-1 after=tfb-1 -> STABLE across node replacement
  ...20/200
  ...40/200
  ...60/200
  ...80/200
  ...100/200
  ...120/200
  ...140/200
  ...160/200
  ...180/200
  ...200/200
GATE B: runs=200
  TFBthumb  flakes=0  median settle=1708ms
  baseline  flakes=130  median settle=562ms
  latency win: 0.3x faster to a confirmed-settled state
PHASE 2 GATE: PASS -- identity survives re-render; 0 premature settles; win measured vs screenshot loop