## Link to GitHub Issue or related Pull Request, if one exists
#720
## Description of change
Pass `VK_F4` sys-key messages through to `DefWindowProc` before ImGui
ingestion, restoring the normal Alt+F4 -> `WM_CLOSE` ->
`launcher::shutdown()` path.
## Testing
- [x] Launch `spicecfg` (D3D9 default path) and press Alt+F4; window
closes and process exits
- [x] Launch `spicecfg` (software path) and press Alt+F4; window closes
and process exits
- [x] Close via title-bar X; still works
## Description of change
**Configurator (spicecfg.exe)**
- Attempts to create a D3D9 device on startup and uses the hardware
ImGui DX9 path when successful; falls back to the existing software
rasterizer automatically if D3D9 init fails.
- Rewrites the configurator window loop: refresh-rate-aware render
timer, minimize/resize/`WM_DISPLAYCHANGE` handling, direct Win32 ->
ImGui input (keyboard, mouse, wheel), and optimized software painting
via `SetDIBitsToDevice` instead of per-frame GDI `HBITMAP` allocation.
**Overlay / input (scoped to standalone configurator)**
- Skips expensive per-frame rawinput polling in
`ImGui_ImplSpice_NewFrame` when `CONFIGURATOR_STANDALONE` is set (Win32
messages drive input instead).
- Adds software-renderer idle-frame detection (`sw_pixels_dirty` +
draw-data hash) so spicecfg only repaints when pixels actually change.
- Adds `ImGuiWindowFlags_NoScrollWithMouse` on the configurator root
window to prevent scroll jolt on non-scrollable child widgets.
drmext