🐞 Avoid cursor stutter when suppressing Mission Control

[jvanderen1]

Description

With Suppress Mission Control enabled, dragging a window to the top of the screen stutters. #609 reported this and was closed by turning the toggle off. The stutter is still in current develop when the toggle stays on. Tracked again in #1159.

Why: Loop keeps Mission Control closed by warping the cursor 1px down on every drag event (CGWarpMouseCursorPosition). That fights the upward drag, so the cursor thrashes.

Fix: Use an active event tap and rewrite the drag event’s location instead. macOS never sees a sustained top-edge hit, and the cursor is not warped.

Rewriting starts on the first drag event, before the window lookup finishes, because Mission Control can open on those events. If the drag is not a window, rewriting stops. The display is resolved with CoreGraphics on the event-tap thread rather than AppKit. Suppression still follows the Suppress Mission Control setting.

Fixes #1159

How has this been tested?

Local Debug build on macOS 27.0 (also checked earlier on macOS Tahoe):

• Suppress on + drag to top and hold — cursor stays smooth, Mission Control does not open
• Top snap preview still appears and applies on mouse up
• Suppress off — Mission Control can still open from a top-edge window drag
• Unit tests for which display edge is rewritten, including stacked displays and a shared corner

Worth a look on a second display, and while dragging something that is not a window (suppression should stop once that lookup fails).

Screencast

output.mp4

Checklist:

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if applicable
• I have no unrelated changes in this PR.

Please describe to which degree, if any, an LLM was used in creating this pull request.

Cursor (Grok) helped investigate the stutter and draft the change in WindowDragManager, including the later event-tap hardening. I reviewed the code, confirmed it builds, and manually tested top-edge dragging before opening this PR.

[jvanderen1]

@mrkai77 I was wondering if you had q chance to see this PR? I have noticed the "Supress Misson Control" option in Loop was quite laggy on the top edge. This resolves that issue.