fix(desktop-client): make settings window a child of main window on Windows

Sets the settings window parent on creation and re-applies it on reveal
so it stays modal to the main window on win32.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/desktop-client/src/main/bootstrap.ts

@@ -466,9 +466,20 @@ function queueWindowModeSwitch(
 
 async function openSettingsWindow(): Promise<void> {
   const window = await ensureSettingsWindow();
+  const parent = settingsWindowParent();
+  if (parent && window.getParentWindow() !== parent) {
+    window.setParentWindow(parent);
+  }
   await revealWindow(window);
 }
 
+function settingsWindowParent(): ElectronBrowserWindow | undefined {
+  if (process.platform !== "win32") {
+    return undefined;
+  }
+  return currentMainWindow() ?? undefined;
+}
+
 function rendererURL(): string | null {
   return process.env.ELECTRON_RENDERER_URL ?? null;
 }
@@ -598,6 +609,7 @@ async function createSettingsWindow(): Promise<ElectronBrowserWindow> {
   const initial = SETTINGS_WINDOW_SIZE;
   const backgroundColor = nativeTheme.shouldUseDarkColors ? "#15191a" : "#f2f4f7";
   const window = new BrowserWindow({
+    parent: settingsWindowParent(),
     width: initial.width,
     height: initial.height,
     minWidth: initial.minWidth,