fix(reader): add Always on Top toggle to reader view, closes #3482 (#3505)

- Apply alwaysOnTop setting on reader window init so books opened
  in a new window correctly inherit the setting
- Update tauriHandleSetAlwaysOnTop to apply to all open windows
  so toggling from any window keeps all windows in sync

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/readest-app/src/app/reader/page.tsx

@@ -6,6 +6,7 @@ import { useTranslation } from '@/hooks/useTranslation';
 import { useOpenWithBooks } from '@/hooks/useOpenWithBooks';
 import { useSettingsStore } from '@/store/settingsStore';
 import { checkForAppUpdates, checkAppReleaseNotes } from '@/helpers/updater';
+import { tauriHandleSetAlwaysOnTop } from '@/utils/window';
 import Reader from './components/Reader';
 
 // This is only used for the Tauri app in the app router
@@ -24,6 +25,9 @@ export default function Page() {
         checkAppReleaseNotes();
       }
     };
+    if (appService?.hasWindow && settings.alwaysOnTop) {
+      tauriHandleSetAlwaysOnTop(settings.alwaysOnTop);
+    }
     doCheckAppUpdates();
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [appService?.hasUpdater, settings.autoCheckUpdates]);

apps/readest-app/src/utils/window.ts

@@ -1,4 +1,4 @@
-import { getCurrentWindow } from '@tauri-apps/api/window';
+import { getAllWindows, getCurrentWindow } from '@tauri-apps/api/window';
 import { emitTo, TauriEvent } from '@tauri-apps/api/event';
 import { exit } from '@tauri-apps/plugin-process';
 import { type as osType } from '@tauri-apps/plugin-os';
@@ -76,8 +76,8 @@ export const tauriHandleToggleFullScreen = async () => {
 };
 
 export const tauriHandleSetAlwaysOnTop = async (isAlwaysOnTop: boolean) => {
-  const currentWindow = getCurrentWindow();
-  await currentWindow.setAlwaysOnTop(isAlwaysOnTop);
+  const windows = await getAllWindows();
+  await Promise.all(windows.map((w) => w.setAlwaysOnTop(isAlwaysOnTop)));
 };
 
 export const tauriGetAlwaysOnTop = async () => {