Correct stale Dock insets during window actions

[culpen90]

Summary

• refresh Dock placement when AppKit reports a stale visible frame
• repair missing and phantom Dock reservations after display, edge, and auto-hide changes
• preserve menu bar and notch boundaries while failing closed on ambiguous accessibility geometry
• add coverage for Dock placements, display moves, auto-hide, invalid geometry, and combined displays

Root cause

macOS can leave NSScreen.visibleFrame stale after Dock preference or display-topology changes. Rectangle used that frame directly, so the first Maximize or related action could overlap the Dock or retain space for its former location.

Testing

• DockVisibleFrameTests: 16 passed
• full Rectangle test suite: 250 passed
• git diff --check

Fixes #467
Related to #1674