Show Windows 11 Snap Layouts flyout on the maximize button

[Gabriel Dufresne (GabrielDuf)]

This pull request adds support for Windows 11 Snap Layouts integration with the custom maximize button in the main window. It ensures that the maximize button correctly reports its hit test area to Windows, allowing the Snap Layouts flyout to appear, and emulates proper hover and press visuals for a consistent user experience. Several native interop methods and structures are introduced to handle these new interactions.

Snap Layouts Integration and Button Behavior:

• Added handling for relevant Windows messages (WM_NCHITTEST, WM_NCMOUSEMOVE, etc.) in the window procedure to report the maximize button area as HTMAXBUTTON, enabling Snap Layouts support and emulating hover/press/click visuals for the custom maximize button.
• Implemented HitTestMaximizeButton to determine if a screen point is within the maximize button, and SetMaximizeButtonVisual to update its appearance based on hover/press state.
• Introduced internal state fields (_maxButtonHover, _maxButtonPressed) to track the maximize button's visual state.

Native Methods and Structures:

• Added P/Invoke declarations for PostMessage and TrackMouseEvent, and defined the TRACKMOUSEEVENT struct to support non-client mouse tracking and message posting.

Constants:

• Introduced several Windows message and hit test constants necessary for handling non-client maximize button interactions.