Initial Task C commit (77c2a1d) used handle constructors and import paths
that match windows-rs 0.58+, not the 0.54 version pinned via the
workspace's transitive 'windows' dep. Compile errors on the Korean
Windows 11 build:
* HWND/HHOOK/HRAWINPUT take 'pub isize' in 0.54 (became raw pointers
in 0.58). Use HWND(HWND_MESSAGE_PTR), HHOOK(0), HRAWINPUT(lparam.0)
instead of *mut _ casts.
* CreateWindowExW returns HWND directly in 0.54, not Result<HWND>.
Check hwnd.0 == 0 for null.
* RegisterClassExW + WNDCLASSEXW are gated behind Win32_Graphics_Gdi
in 0.54. Added that feature.
* XBUTTON1 / XBUTTON2 live in Win32::UI::WindowsAndMessaging not
Win32::UI::Input::KeyboardAndMouse in 0.54.
* Win32_System_Threading needed for GetCurrentThreadId.
* Unused Mutex import dropped.
No behavioural change relative to 77c2a1d; just signature alignment.