fix(desktop): wakelock issue with multiple tabs in same window (#13956)

Each desktop isolate now independently tracks wakelock state.
  WakelockPlus.disable() is only called when all tabs within the
  same isolate are closed/minimized.

  WakelockPlus ensures screen stays awake as long as any isolate
  has wakelock enabled.

Signed-off-by: 21pages <sunboeasy@gmail.com>

flutter/lib/desktop/pages/file_manager_page.dart

@@ -17,7 +17,6 @@ import 'package:flutter_hbb/desktop/widgets/tabbar_widget.dart';
 import 'package:flutter_hbb/models/file_model.dart';
 import 'package:flutter_svg/flutter_svg.dart';
 import 'package:get/get.dart';
-import 'package:wakelock_plus/wakelock_plus.dart';
 import 'package:flutter_hbb/web/dummy.dart'
     if (dart.library.html) 'package:flutter_hbb/web/web_unique.dart';
 
@@ -86,6 +85,7 @@ class _FileManagerPageState extends State<FileManagerPage>
 
   final _dropMaskVisible = false.obs; // TODO impl drop mask
   final _overlayKeyState = OverlayKeyState();
+  final _uniqueKey = UniqueKey();
 
   late FFI _ffi;
 
@@ -107,9 +107,7 @@ class _FileManagerPageState extends State<FileManagerPage>
           .showLoading(translate('Connecting...'), onCancel: closeConnection);
     });
     Get.put<FFI>(_ffi, tag: 'ft_${widget.id}');
-    if (!isLinux) {
-      WakelockPlus.enable();
-    }
+    WakelockManager.enable(_uniqueKey);
     if (isWeb) {
       _ffi.ffiModel.updateEventListener(_ffi.sessionId, widget.id);
     }
@@ -127,9 +125,7 @@ class _FileManagerPageState extends State<FileManagerPage>
     model.close().whenComplete(() {
       _ffi.close();
       _ffi.dialogManager.dismissAll();
-      if (!isLinux) {
-        WakelockPlus.disable();
-      }
+      WakelockManager.disable(_uniqueKey);
       Get.delete<FFI>(tag: 'ft_${widget.id}');
     });
     WidgetsBinding.instance.removeObserver(this);