Remove dxwrapper; test scripts focus the game window

The default render size (1835x768) is below Direct3D 7's 2048 limit, so the
D3D7 -> D3D9 wrapper and its device-info workaround are no longer needed.
The game pauses start-up until its window is active; game-input.ps1 now
activates it reliably (Alt + SetForegroundWindow, polled), which dxwrapper
had masked. borderless logs the first failed presents.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/widescreen.md

@@ -76,9 +76,12 @@ presents only that area, scaled to the monitor.
 Windows' D3D7 runtime refuses `IDirect3D7::CreateDevice` on any render
 target wider or taller than 2048 (`DDERR_INVALIDOBJECT`, 0x88760082),
 measured with a standalone test: 2048x1440 works, 2049x1440 / 2560x1080 /
-3440x1440 fail. Native ultrawide therefore needs dxwrapper (`Dd7to9`,
-D3D7 -> D3D9), see `src/mods/dxwrapper.cpp`; without it the render size is
-clamped to 2048.
+3440x1440 fail. The default render size (768 high, e.g. 1835x768) stays
+below it; larger sizes are clamped to 2048. (A D3D7 -> D3D9 wrapper,
+dxwrapper, lifted the limit but was dropped again in commit history once the
+render size no longer needed it; it also required fixing the device info GUID
+pointer at +4 of SetDisplayMode's first argument, which its enumeration left
+invalid.)
 
 ## Renderer