Fix drag-snap window detection for Emacs 28

[culpen90]

Emacs 28 exposes its window as AXTextField with the AXStandardWindow subrole and no AXWindow attribute. When a hit test returns that window itself, the resolver rejects it, leaving the drag-snap fallback without a target.

Preserve the existing window-role and containing-window paths, then recognize AXStandardWindow as a fallback. Add five regression tests covering the Emacs case and existing window/control behavior.

Validation:

• Full Xcode test suite: 591 tests passed, zero failures.
• Verified with genuine Emacs 28.2: the original resolver returns no window; the updated resolver correctly returns the Emacs window.

Fixes #591