feat: win32 enable dark titlebar for dark theme

Signed-off-by: DavidoTek <54072917+DavidoTek@users.noreply.github.com>

launcher/ui/WinDarkmode.cpp

@@ -0,0 +1,32 @@
+#include <QWidget>
+
+#include "WinDarkmode.h"
+
+namespace WinDarkmode {
+
+/* See https://github.com/statiolake/neovim-qt/commit/da8eaba7f0e38b6b51f3bacd02a8cc2d1f7a34d8 */
+void setDarkWinTitlebar(WId winid, bool darkmode)
+{
+    HWND hwnd = reinterpret_cast<HWND>(winid);
+    BOOL dark = (BOOL) darkmode;
+
+    HMODULE hUxtheme = LoadLibraryExW(L"uxtheme.dll", NULL, LOAD_LIBRARY_SEARCH_SYSTEM32);
+    HMODULE hUser32 = GetModuleHandleW(L"user32.dll");
+    fnAllowDarkModeForWindow AllowDarkModeForWindow
+        = reinterpret_cast<fnAllowDarkModeForWindow>(GetProcAddress(hUxtheme, MAKEINTRESOURCEA(133)));
+    fnSetPreferredAppMode SetPreferredAppMode
+        = reinterpret_cast<fnSetPreferredAppMode>(GetProcAddress(hUxtheme, MAKEINTRESOURCEA(135)));
+    fnSetWindowCompositionAttribute SetWindowCompositionAttribute
+        = reinterpret_cast<fnSetWindowCompositionAttribute>(GetProcAddress(hUser32, "SetWindowCompositionAttribute"));
+
+    SetPreferredAppMode(AllowDark);
+    AllowDarkModeForWindow(hwnd, dark);
+    WINDOWCOMPOSITIONATTRIBDATA data = {
+        WCA_USEDARKMODECOLORS,
+        &dark,
+        sizeof(dark)
+    };
+    SetWindowCompositionAttribute(hwnd, &data);
+}
+
+}