fix(cli): ignore ancestor motion in pivot drift audit

packages/cli/src/commands/layout-audit.browser.js

@@ -1546,6 +1546,15 @@
     return (Math.atan2(b, a) * 180) / Math.PI;
   }
 
+  function ancestorTransformSignature(element, root) {
+    const transforms = [];
+    for (let ancestor = element.parentElement; ancestor; ancestor = ancestor.parentElement) {
+      transforms.push(getComputedStyle(ancestor).transform || "none");
+      if (ancestor === root) break;
+    }
+    return transforms.join("|");
+  }
+
   window.__hyperframesRotationSample = function collectRotationSample() {
     const root =
       document.querySelector("[data-composition-id][data-width][data-height]") ||
@@ -1572,6 +1581,7 @@
         w: round(box.width),
         h: round(box.height),
         angle: round(angle),
+        ancestorTransformSignature: ancestorTransformSignature(element, root),
       });
     }
     return samples;

packages/cli/src/utils/checkBrowser.ts

@@ -559,10 +559,19 @@ function parseRotationSample(value: unknown, time: number): RotationSample[] {
   const w = numberValue(value, "w");
   const h = numberValue(value, "h");
   const angle = numberValue(value, "angle");
-  if (!selector || cx === null || cy === null || w === null || h === null || angle === null) {
+  const ancestorTransformSignature = stringValue(value, "ancestorTransformSignature");
+  if (
+    !selector ||
+    cx === null ||
+    cy === null ||
+    w === null ||
+    h === null ||
+    angle === null ||
+    ancestorTransformSignature === null
+  ) {
     return [];
   }
-  return [{ time, selector, cx, cy, w, h, angle }];
+  return [{ time, selector, cx, cy, w, h, angle, ancestorTransformSignature }];
 }
 
 async function collectOffPivotRotationSample(page: Page, time: number): Promise<OffPivotFrame> {

packages/cli/src/utils/checkPipeline.rotationPivotDrift.test.ts

@@ -15,7 +15,17 @@ function rotatedAabb(elemW: number, elemH: number, angleDeg: number): { w: numbe
 
 /** One rotation sample; defaults describe a large square. */
 function sample(overrides: Partial<RotationSample> = {}): RotationSample {
-  return { time: 0, selector: "#spokes", cx: 250, cy: 250, w: 200, h: 200, angle: 0, ...overrides };
+  return {
+    time: 0,
+    selector: "#spokes",
+    cx: 250,
+    cy: 250,
+    w: 200,
+    h: 200,
+    angle: 0,
+    ancestorTransformSignature: "none",
+    ...overrides,
+  };
 }
 
 /** Rigid rectangle sample: AABB is derived from unrotated size + angle. */
@@ -176,6 +186,25 @@ describe("detectRotationPivotDrift", () => {
     expect(detectRotationPivotDrift(group, CANVAS)).toHaveLength(0);
   });
 
+  it("does not attribute translating ancestor motion to the child's rotation pivot", () => {
+    const group = [
+      {
+        ...rigidSample(220, 220, { time: 0, angle: 0, cx: 200, cy: 250 }),
+        ancestorTransformSignature: "matrix(1, 0, 0, 1, 0, 0)",
+      },
+      {
+        ...rigidSample(220, 220, { time: 1, angle: 90, cx: 450, cy: 250 }),
+        ancestorTransformSignature: "matrix(1, 0, 0, 1, 250, 0)",
+      },
+      {
+        ...rigidSample(220, 220, { time: 2, angle: 180, cx: 700, cy: 250 }),
+        ancestorTransformSignature: "matrix(1, 0, 0, 1, 500, 0)",
+      },
+    ];
+
+    expect(detectRotationPivotDrift(group, CANVAS)).toHaveLength(0);
+  });
+
   it("uses the viewport floor when the element is small relative to a large canvas", () => {
     // medianSize≈200 → sizeFloor=20; viewportFloor on a 3000px canvas = 60.
     // A 40px drift is below 60 → clean; the same group fired on CANVAS above.

packages/cli/src/utils/checkPipeline.ts

@@ -717,13 +717,20 @@ function isSizableRotation(group: RotationSample[]): boolean {
   return median(group.map((s) => s.w * s.h)) >= ROTATION_MIN_MEDIAN_AREA_PX;
 }
 
+/** Viewport-center motion is ambiguous while an ancestor transform changes:
+ * it may be carrying an otherwise correctly pivoted child across the canvas. */
+function hasStableAncestorTransforms(group: RotationSample[]): boolean {
+  return new Set(group.map((sample) => sample.ancestorTransformSignature)).size === 1;
+}
+
 /** Size/motion FP gates before the viewport-dependent center-drift test. */
 function isRotationDriftCandidate(group: RotationSample[]): boolean {
   return (
     hasEnoughRotationSamples(group) &&
     isActuallySpinning(group) &&
     isRotationSizeStable(group) &&
-    isSizableRotation(group)
+    isSizableRotation(group) &&
+    hasStableAncestorTransforms(group)
   );
 }
 

packages/cli/src/utils/checkTypes.ts

@@ -141,6 +141,9 @@ export interface RotationSample {
   w: number;
   h: number;
   angle: number;
+  /** Computed-transform chain above this element, used to distinguish a bad
+   * local pivot from viewport motion introduced by an animated ancestor. */
+  ancestorTransformSignature: string;
 }
 
 /** One elongated rotating SVG figure's material geometry at a single seeked