fix(mobile-app): 修复账本明细筛选栏滚动重置问题

使用 ScrollController 保持筛选栏滚动位置

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/mobile-app/lib/features/trading/presentation/pages/ledger_detail_page.dart

@@ -15,6 +15,7 @@ class LedgerDetailPage extends ConsumerStatefulWidget {
 class _LedgerDetailPageState extends ConsumerState<LedgerDetailPage>
     with SingleTickerProviderStateMixin {
   late TabController _tabController;
+  late ScrollController _filterScrollController;
 
   // 数据状态
   bool _isLoading = true;
@@ -25,6 +26,7 @@ class _LedgerDetailPageState extends ConsumerState<LedgerDetailPage>
 
   // 筛选条件
   String? _selectedEntryType;
+  int _selectedFilterIndex = 0;
   int _currentPage = 1;
   static const int _pageSize = 20;
 
@@ -45,12 +47,14 @@ class _LedgerDetailPageState extends ConsumerState<LedgerDetailPage>
   void initState() {
     super.initState();
     _tabController = TabController(length: 2, vsync: this);
+    _filterScrollController = ScrollController();
     _loadData();
   }
 
   @override
   void dispose() {
     _tabController.dispose();
+    _filterScrollController.dispose();
     super.dispose();
   }
 
@@ -125,9 +129,10 @@ class _LedgerDetailPageState extends ConsumerState<LedgerDetailPage>
   }
 
   /// 筛选流水类型
-  Future<void> _filterByEntryType(String? entryType) async {
+  Future<void> _filterByEntryType(String? entryType, int index) async {
     setState(() {
       _selectedEntryType = entryType?.isEmpty == true ? null : entryType;
+      _selectedFilterIndex = index;
       _currentPage = 1;
       _isLoading = true;
     });
@@ -771,15 +776,16 @@ class _LedgerDetailPageState extends ConsumerState<LedgerDetailPage>
       height: 44,
       margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
       child: ListView.builder(
+        controller: _filterScrollController,
         scrollDirection: Axis.horizontal,
         itemCount: _entryTypes.length,
         itemBuilder: (context, index) {
           final type = _entryTypes[index];
-          final isSelected = (_selectedEntryType ?? '') == type['value'];
+          final isSelected = _selectedFilterIndex == index;
           return Padding(
             padding: const EdgeInsets.only(right: 8),
             child: GestureDetector(
-              onTap: () => _filterByEntryType(type['value']),
+              onTap: () => _filterByEntryType(type['value'], index),
               child: Container(
                 padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
                 decoration: BoxDecoration(