feat: optimize log viewer with chunked loading and auto-scroll

- Implement chunked loading for large log files
- Add auto-scroll toggle with immediate scroll to bottom

Author: 3003h

lib/common/controller/log_controller.dart

@@ -14,6 +14,11 @@ const _kSuffix = '.log';
 class LogService extends GetxController {
   final logFiles = <File>[].obs;
 
+  // 添加自动滚动控制
+  final _autoScroll = true.obs;
+  bool get autoScroll => _autoScroll.value;
+  set autoScroll(bool val) => _autoScroll.value = val;
+
   final _curFileName = 'eh.log'.obs;
   String get curFileName => _curFileName.value;
   set curFileName(String val) => _curFileName.value = val;

lib/main.dart

@@ -180,6 +180,7 @@ class _MyAppState extends State<MyApp> with WidgetsBindingObserver {
   @override
   void dispose() {
     WidgetsBinding.instance.removeObserver(this);
+    _listener.dispose();
     super.dispose();
   }