Make the actor smoke reach every sub pixel edge position again

Since #225 the game view opens at 100 % instead of fit. The actor walks
150 px/s, so its top edge only lands on .0 or .5 of a pixel. The check
for the frame top edge needs 0.6 to 0.9 and gave up in 6 of 7 CI runs.
The picture itself was fine: the pixels above and at the edge were the
same in every red run.

- While nudging the actor into place the smoke slows time to 0.08 with
  __gm.setTimeScale. The actor then moves 0.2 px per frame and can
  reach any position inside a pixel.
- Time scale goes back to 1 before the edge is measured.

Tests:
- Old smoke on the same seeded project fails locally like CI
  (fraction 0.08).
- New smoke passed three times in a row (fraction 0.80, 21 checks).
- The actor project file was saved first and restored byte exact.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tools/smoke-actor.mjs

@@ -38,7 +38,21 @@ const walkOf = (e) =>
 const rowOfFrame = (texture) => Number(String(texture).split('-')[1]);
 
 await runChecks({ projectId, baseUrl, port: 9341, shotPrefix: 'gm-actor' }, async (t) => {
-  const { check, sleep, json, shot, entity, play, stop, navigate, exceptions, holdKey, keyDown, keyUp } = t;
+  const {
+    check,
+    sleep,
+    json,
+    evaluate,
+    shot,
+    entity,
+    play,
+    stop,
+    navigate,
+    exceptions,
+    holdKey,
+    keyDown,
+    keyUp,
+  } = t;
 
   await navigate();
 
@@ -257,10 +271,13 @@ await runChecks({ projectId, baseUrl, port: 9341, shotPrefix: 'gm-actor' }, asyn
   // 12. A frame's top edge shows nothing of the cell above it, wherever the edge lands inside a
   //     pixel. Drawn from the sheet, a partly covered edge pixel read the boots of the cell above –
   //     the hairline over the head. Nudged upwards until the edge sits in the lower half of a pixel.
+  //     At the game view's 100% a frame at full speed moves 2.5 px, so the edge only ever lands on
+  //     .0 or .5. Slowed to 0.2 px a frame, it walks through every part of a pixel.
   const topEdge = async () => {
     const r = await json(`__gm.gameRect('oplayer')`);
     return { cx: Math.round(r.x), y0: r.y - r.h / 2 };
   };
+  await evaluate('__gm.setTimeScale(0.08)');
   let edge;
   let nudges = 0;
   do {
@@ -269,6 +286,7 @@ await runChecks({ projectId, baseUrl, port: 9341, shotPrefix: 'gm-actor' }, asyn
     edge = await topEdge();
     nudges += 1;
   } while (nudges < 40 && !(edge.y0 % 1 > 0.6 && edge.y0 % 1 < 0.9));
+  await evaluate('__gm.setTimeScale(1)');
   const facingUp = await entity('oplayer');
   const rowAt = async (y) =>
     json(`[-8,-6,-4,-2,0,2,4,6,8].map((dx) => __gm.pixelAt(${edge.cx} + dx, ${y}))`).then((p) => p.join(' '));