sdvx: fix api touch in windowed mode (#862)

## Link to GitHub Issue or related Pull Request, if one exists
Fixes #858 

## Description of change
Fix orientation being wrong in windowed mode when API touch is used

Fix mouse no longer working when API client is in use.

This PR only affects windowed mode SDVX.

## Testing

src/spice2x/touch/native/transform.cpp

@@ -147,6 +147,12 @@ namespace nativetouch::transform {
             return screen_to_game(window, position);
         }
 
+        // exception: sdvx windowed subscreen does not use the subscreen overlay transform
+        if (GRAPHICS_WINDOWED && window == SDVX_SUBSCREEN_WINDOW) {
+            POINT client_position = *position;
+            return screen_to_game_client(window, &client_position);
+        }
+
         // if this game has a subscreen overlay that can transform touch input
         // but the window is hidden or not under the cursor, reject mouse-as-touch
         // (e.g., iidx/sdvx are rejected here, but nostalgia is allowed)