bcb4d683f08d  [AppKit Gestures] Mouse hold is not reported to web content until the press ends

Classified as not security-relevant.
Triage note: Adds a new off-by-default preference UseAppKitGesturesForPointerEvents and a WKPointerTrackingGestureRecognizer/dispatchTrackedPointerEvent pipeline that drives DOM pointer events directly; the tracked-pointer path only engages for inputSource==Automation with the setting enabled. Large new feature (plus a refactor extracting dispatchBoundaryEvents), not a security fix.
This commit was flagged by the signal scorer and reviewed by AI (not a human). It is listed only so the triage is auditable; there is no root-cause analysis because this is not a vulnerability fix.

Structural signals: smartptr_member_added (+6.47), security_assert (+3.0), null_guard (+2.59), uaf_lifetime (+4.75), clamp_saturate (+1.8), area:Source/WebCore/dom (+2.0), large_churn (-2.0)