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>

implementations/Crafter.Graphics-Device.cpp

@@ -493,10 +493,7 @@ void Device::PointerListenerHandleMotion(void* data, wl_pointer* wl_pointer, std
 		return;
 	}
 	Vector<float, 2> pos(wl_fixed_to_double(surface_x), wl_fixed_to_double(surface_y));
-	//Device::focusedWindow->lastMousePos = Device::focusedWindow->currentMousePos;
-	Device::focusedWindow->currentMousePos = pos * Device::focusedWindow->scale;
-	//Device::focusedWindow->mouseDelta = {Device::focusedWindow->currentMousePos.x-Device::focusedWindow->lastMousePos.x, Device::focusedWindow->currentMousePos.y-Device::focusedWindow->lastMousePos.y};
-	Device::focusedWindow->onMouseMove.Invoke();
+	Device::focusedWindow->PointerMove(pos * Device::focusedWindow->scale);
 }
 
 void Device::PointerListenerHandleEnter(void* data, wl_pointer* wl_pointer, std::uint32_t serial, wl_surface* surface, wl_fixed_t surface_x, wl_fixed_t surface_y) {
@@ -509,7 +506,12 @@ void Device::PointerListenerHandleEnter(void* data, wl_pointer* wl_pointer, std:
                                       window->cursorHotspotX_, window->cursorHotspotY_);
             }
             focusedWindow = window;
-            window->onMouseEnter.Invoke();
+            const Vector<float, 2> pos = Vector<float, 2>(wl_fixed_to_double(surface_x), wl_fixed_to_double(surface_y)) * window->scale;
+            window->PointerEnter(pos);
+            // ~Window clears focusedWindow, should a listener destroy it.
+            if (focusedWindow == window) {
+                window->PointerMove(pos);
+            }
             return;
         }
     }
@@ -519,12 +521,9 @@ void Device::PointerListenerHandleLeave(void* data, wl_pointer*, std::uint32_t,
     // Sway has been observed to send a second leave after focus is already
     // gone (input-device hot-plug) — don't crash on it.
     if (focusedWindow != nullptr) {
-        focusedWindow->onMouseLeave.Invoke();
+        focusedWindow->PointerLeave();
         focusedWindow = nullptr;
     }
-    // Drop any sub-detent scroll remainder so it can't leak into whatever
-    // window the pointer enters next.
-    scrollDetentRemainder = 0.0;
 }
 
 void Device::PointerListenerHandleAxis(void*, wl_pointer*, std::uint32_t, std::uint32_t axis, wl_fixed_t value) {
@@ -535,18 +534,11 @@ void Device::PointerListenerHandleAxis(void*, wl_pointer*, std::uint32_t, std::u
     // libinput convention (followed by wlroots, Mutter and KWin): one wheel
     // detent = 15 axis units, positive = wheel down / toward the user — the
     // same sign as DOM deltaY. Window::onMouseScroll speaks whole detents
-    // (±1 per notch on every backend), so divide and accumulate the
-    // remainder: smooth-scroll devices (touchpads) deliver many sub-detent
-    // events that must add up instead of each truncating to zero.
+    // (±1 per notch on every backend), so divide; smooth-scroll devices
+    // (touchpads) deliver many sub-detent events, which PointerScroll adds
+    // up instead of each truncating to zero.
     constexpr double axisUnitsPerDetent = 15.0;
-    scrollDetentRemainder += wl_fixed_to_double(value) / axisUnitsPerDetent;
-    const double whole = std::trunc(scrollDetentRemainder);
-    if (whole != 0.0) {
-        scrollDetentRemainder -= whole;
-        // Event payload is uint32 — preserve sign via two's complement.
-        focusedWindow->onMouseScroll.Invoke(
-            static_cast<std::uint32_t>(static_cast<std::int32_t>(whole)));
-    }
+    focusedWindow->PointerScroll(wl_fixed_to_double(value) / axisUnitsPerDetent);
 }