Fix touch gestures cancelling, backward flicks, and late onCommit

- Only the host's own lostpointercapture cancels a gesture. Taking
  capture makes the touched child lose its implicit touch capture, and
  that bubbling event was cancelling every touch gesture immediately.
- A flick at least commitVelocity fast now decides by its direction:
  backward cancels even past the distance threshold, forward commits.
  Slower releases still decide by distance.
- Pointer-up finishes an already-begun operation without awaiting, so
  onCommit runs inside the pointer-up event, where iOS still allows
  haptics, audio, and clipboard writes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Faarh2Ts6StJPcz2mRiHiR

packages/core-v2/src/scene/graph.ts

@@ -73,17 +73,22 @@ export const DEFAULT_COMMIT_THRESHOLD = 0.36;
  */
 export const DEFAULT_COMMIT_VELOCITY = 0.3;
 
-/** Decide a release outcome from explicit options or progress/velocity. */
+/**
+ * Decide a release outcome from explicit options, or from velocity and
+ * progress: a flick at least `commitVelocity` fast decides by its direction,
+ * forward committing and backward cancelling, regardless of distance. Slower
+ * releases commit once progress reaches `commitThreshold`.
+ */
 export const shouldCommit = (
   operation: MutableOriginOperation,
   options: OriginFinishOptions,
 ): boolean => {
   if (options.commit !== undefined) return options.commit;
   const { commitThreshold, commitVelocity } = operation.choreography;
-  return (
-    operation.progress >= (commitThreshold ?? DEFAULT_COMMIT_THRESHOLD) ||
-    operation.velocity >= (commitVelocity ?? DEFAULT_COMMIT_VELOCITY)
-  );
+  const flick = commitVelocity ?? DEFAULT_COMMIT_VELOCITY;
+  if (operation.velocity >= flick) return true;
+  if (operation.velocity <= -flick) return false;
+  return operation.progress >= (commitThreshold ?? DEFAULT_COMMIT_THRESHOLD);
 };
 
 /**