追加webdav重新登录的button，还在测试边界情况

lib/pages/home_page.dart

@@ -7,6 +7,7 @@ import '../widgets/magnetic_scroll_physics.dart';
 import 'webdav_setup_page.dart';
 import 'webdav_file_list_page.dart';
 import '../constants/ui_constants.dart';
+import '../base/base_state.dart';
 
 // ==================================================
 // 歌曲数据模型
@@ -149,7 +150,7 @@ class HomePage extends StatefulWidget {
   State<HomePage> createState() => _HomePageState();
 }
 
-class _HomePageState extends State<HomePage> {
+class _HomePageState extends BaseState<HomePage> {
   List<SongItem> _favorites = [];
   bool _isLoading = true;
 
@@ -282,6 +283,52 @@ class _HomePageState extends State<HomePage> {
     }
   }
 
+  // ⭐ 退出/重新登录对话框
+  void _showReauthDialog() {
+    showDialog(
+      context: context,
+      builder: (context) => AlertDialog(
+        backgroundColor: const Color(0xFF1A1F1E),
+        title: const Text(
+          '重新登录 WebDAV',
+          style: TextStyle(color: Colors.white),
+        ),
+        content: const Text(
+          '退出当前账号并重新登录？',
+          style: TextStyle(color: Colors.grey),
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(context),
+            child: const Text('取消'),
+          ),
+          TextButton(
+            onPressed: () async {
+              Navigator.pop(context);
+              await WebDAVService.instance.clearCredentials();
+              setState(() {
+                _favorites = [];
+                _isLoading = false;
+              });
+              if (mounted) {
+                Navigator.pushReplacement(
+                  context,
+                  MaterialPageRoute(
+                    builder: (_) => const WebDAVSetupPage(),
+                  ),
+                );
+              }
+            },
+            child: const Text(
+              '重新登录',
+              style: TextStyle(color: Colors.redAccent),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
   void _resetSnapState() {
     if (_scrollController.hasClients) {
       _scrollController.jumpTo(0.0);
@@ -413,6 +460,25 @@ class _HomePageState extends State<HomePage> {
                                               fontWeight: FontWeight.w400,
                                             ),
                                           ),
+                                          // ⭐ 退出按钮（已连接时显示）
+                                          if (isConnected) ...[
+                                            const Spacer(),
+                                            IconButton(
+                                              icon: const Icon(
+                                                Icons.logout,
+                                                color: Colors.grey,
+                                                size: 18,
+                                              ),
+                                              tooltip: '重新登录',
+                                              onPressed: _showReauthDialog,
+                                              padding: EdgeInsets.zero,
+                                              constraints: const BoxConstraints(
+                                                minWidth: 32,
+                                                minHeight: 32,
+                                              ),
+                                            ),
+                                            const SizedBox(width: 4),
+                                          ],
                                         ],
                                       ),
                                       const SizedBox(height: 4),