graphics: respect Windows dark mode (#765)

Only affects the caption bar.

Should work for:

- [x] standalone configurator
- [x] dx9 games, including multi-window games like gitadora
- [x] Unity games

src/spice2x/hooks/graphics/graphics.cpp

@@ -585,6 +585,9 @@ static HWND WINAPI CreateWindowExA_hook(DWORD dwExStyle, LPCSTR lpClassName, LPC
             hWndParent, hMenu, hInstance, lpParam);
     GRAPHICS_WINDOWS.push_back(result);
 
+    // theme the native title bar (dark/light)
+    set_window_dark_titlebar(result);
+
     if (is_tdj_sub_window) {
         // TDJ windowed mode: remember the subscreen window handle for later
         TDJ_SUBSCREEN_WINDOW = result;
@@ -706,6 +709,9 @@ static HWND WINAPI CreateWindowExW_hook(DWORD dwExStyle, LPCWSTR lpClassName, LP
             hWndParent, hMenu, hInstance, lpParam);
     GRAPHICS_WINDOWS.push_back(result);
 
+    // theme the native title bar (dark/light)
+    set_window_dark_titlebar(result);
+
     log_misc(
         "graphics",
         "CreateWindowExW returned {}, {}",