fix(win32): restore mouse moves, add enter and leave, capture drags, and close and destroy windows cleanly

Win32
- WM_MOUSEMOVE is handled again: c9ebd44 put the WM_CHAR case where it
  was, so currentMousePos stopped following the mouse and onMouseMove
  never fired. Positions are read signed (GET_X_LPARAM), since under
  capture they run past the client area.
- onMouseEnter and onMouseLeave. The first move over the client area
  after a leave is the enter, and arms the TME_LEAVE whose WM_MOUSELEAVE
  is the leave. An enter counts only once that is armed, a leave only
  after an enter, and a move past the client area is a move only.
- A press captures the mouse, so a drag that leaves the window still
  sends its moves and its release, as Wayland's implicit grab does.
  Losing the capture releases what is held, and a button-up without its
  press fires nothing.
- WM_CLOSE fires onClose and clears open, as xdg_toplevel.close does,
  instead of destroying the HWND under the swapchain. WM_DESTROY no
  longer posts WM_QUIT, which nothing read.
- ~Window detaches the HWND and destroys it. It stayed on screen, and its
  messages went to the freed Window. WndProc hands messages without a
  Window to DefWindowProc, and looks the Window up again after an event
  that more work follows, in case a listener destroyed it.
- The constructor's message pump leaves input queued for StartSync: the
  WM_MOUSEMOVE sent when a window appears under the cursor made an
  onMouseEnter nobody could hear yet. The mouse state is reset before
  the platform code, no longer after it.
- A window after the first finds its class registered, which showed an
  error box.
- The wheel remainder is the window's, no longer a function static that
  every window shared, and a leave drops it.

Window
- PointerEnter, PointerMove, PointerLeave and PointerScroll hold the rules
  both native backends report the pointer by. An enter puts the entry
  position in currentMousePos before onMouseEnter fires, and is followed
  by a move, on Wayland too now. scrollRemainder replaces
  Device::scrollDetentRemainder, and mouseInside is shared.

Tests
- PointerEnterLeave: enter, move and leave through the wl_pointer
  callbacks.
- PointerWin32: posts a real HWND the messages above and pumps them as
  StartSync does. Built for x86_64-w64-mingw32 it runs under Wine, and is
  skipped where Wine is not on PATH.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

interfaces/Crafter.Graphics-Device.cppm

@@ -83,12 +83,6 @@ export namespace Crafter {
         // the manager — Clipboard::SetText silently no-ops there.
         inline static wl_data_device_manager* dataDeviceManager = nullptr;
         inline static wl_data_device* dataDevice = nullptr;
-        // Sub-detent scroll accumulator for PointerListenerHandleAxis.
-        // wl_pointer.axis values are normalized to wheel detents (15 axis
-        // units each, the libinput convention); whatever doesn't make a
-        // whole detent yet is carried here so smooth-scroll devices add up
-        // across events. Reset on pointer leave.
-        inline static double scrollDetentRemainder = 0.0;
         // zwp_text_input_v3: one object per seat; the compositor says which
         // surface it follows (enter/leave), the events are state that done()
         // applies as a whole.