nost: move nostalgia from wintouchemu to native touch hook (#827)

## Link to GitHub Issue or related Pull Request, if one exists
#814

## Description of change
Switch over Nostalgia from wintouchemu to native touch hook.

Nostalgia has some strict timing requirements (touches must be updated
on every acio poll) so this takes a slightly different path to maintain
mouse holds.

Only a handful of consumers of wintouchemu remain:

1. beatstream - but it's off by default, only enabled as errata for
buggy touchscreens, or if the user forces it on (for Show Cursor)
2. gitadora single-window overlay - this is just for mouse so not a big
deal.
3. MFC HG mode - not a priority to fix.

## Testing
Tested full screen and windowed mode with touch / mouse / poke.

src/spice2x/touch/native/inject_synthetic.cpp

@@ -8,6 +8,7 @@
 
 #include "inject.h"
 #include "inject_internal.h"
+#include "settings.h"
 #include "transform.h"
 
 #include "util/logging.h"
@@ -38,10 +39,10 @@ namespace nativetouch::inject {
 
     // synthetic touches preempt the mouse and keep it disabled until release or timeout
     static void begin_synthetic_contact(HWND window, POINT position, bool screen_space) {
-        // dedicated TDJ injects into the physical subscreen, so map Windows'
-        // returned coordinates back into the game's touch coordinate space
+        // remember when Windows-returned coordinates must map back into game space
         const auto transform_returned_coordinates =
-            transform::is_tdj_dedicated_subscreen(window);
+            transform::is_tdj_dedicated_subscreen(window) ||
+            settings::SYNTHETIC_TOUCH_USES_CLIENT_COORDINATES;
         if (!screen_space && !transform::game_to_screen(window, &position)) {
             return;
         }