feat: make core pages local-first offline

frontend/lib/features/settings/recycle_bin_page.dart

@@ -6,6 +6,7 @@ import 'package:miaoji_zhang/shared/services/transaction_events.dart';
 import 'package:miaoji_zhang/shared/theme/app_theme.dart';
 import 'package:miaoji_zhang/shared/widgets/category_icon.dart';
 import 'package:miaoji_zhang/shared/widgets/app_controls.dart';
+import 'package:miaoji_zhang/shared/widgets/backend_status_icon.dart';
 
 class RecycleBinPage extends StatefulWidget {
   const RecycleBinPage({super.key});
@@ -17,6 +18,7 @@ class RecycleBinPage extends StatefulWidget {
 class _RecycleBinPageState extends State<RecycleBinPage> {
   List<TxItem> _items = const [];
   bool _loading = true;
+  int _loadRevision = 0;
 
   @override
   void initState() {
@@ -25,15 +27,30 @@ class _RecycleBinPageState extends State<RecycleBinPage> {
   }
 
   Future<void> _load() async {
+    final revision = ++_loadRevision;
     setState(() => _loading = true);
     try {
-      await CurrentLedgerStore.instance.ensureLoaded();
-      final items = await TxApi.recycleBin();
-      if (mounted) setState(() => _items = items);
+      await CurrentLedgerStore.instance.loadCached();
+      final cached = TxApi.recycleBinLocal();
+      if (mounted && revision == _loadRevision) {
+        setState(() {
+          _items = cached;
+          _loading = false;
+        });
+      }
+      final remote = await TxApi.recycleBinRemote();
+      if (mounted && revision == _loadRevision) {
+        setState(() => _items = remote);
+      }
     } catch (error) {
-      if (mounted) _showError(error);
+      if (mounted && revision == _loadRevision && _loading) {
+        setState(() => _loading = false);
+        _showError(error);
+      }
     } finally {
-      if (mounted) setState(() => _loading = false);
+      if (mounted && revision == _loadRevision && _loading) {
+        setState(() => _loading = false);
+      }
     }
   }
 
@@ -48,6 +65,7 @@ class _RecycleBinPageState extends State<RecycleBinPage> {
   }
 
   Future<void> _permanentDelete(TxItem item) async {
+    if (ApiClient.availability.value != BackendAvailability.online) return;
     final confirmed = await _confirm('永久删除', '永久删除后无法恢复，聊天中的账单卡片会显示为已删除。');
     if (!confirmed) return;
     try {
@@ -59,7 +77,10 @@ class _RecycleBinPageState extends State<RecycleBinPage> {
   }
 
   Future<void> _clear() async {
-    if (_items.isEmpty) return;
+    if (_items.isEmpty ||
+        ApiClient.availability.value != BackendAvailability.online) {
+      return;
+    }
     final confirmed = await _confirm('清空回收站', '将永久删除当前账本回收站中的全部账单，无法恢复。');
     if (!confirmed) return;
     try {
@@ -79,12 +100,14 @@ class _RecycleBinPageState extends State<RecycleBinPage> {
   );
 
   Future<void> _showActions(TxItem item) async {
+    final online = ApiClient.availability.value == BackendAvailability.online;
     final action = await showJzOptionSheet<String>(
       context,
       title: item.note ?? item.categoryName,
-      options: const [
-        JzOption(value: 'restore', label: '恢复账单'),
-        JzOption(value: 'delete', label: '永久删除', subtitle: '删除后无法恢复'),
+      options: [
+        const JzOption(value: 'restore', label: '恢复账单'),
+        if (online)
+          const JzOption(value: 'delete', label: '永久删除', subtitle: '删除后无法恢复'),
       ],
     );
     if (action == 'restore') await _restore(item);
@@ -103,9 +126,16 @@ class _RecycleBinPageState extends State<RecycleBinPage> {
       appBar: AppBar(
         title: Text('${CurrentLedgerStore.instance.currentName} · 回收站'),
         actions: [
-          TextButton(
-            onPressed: _items.isEmpty ? null : _clear,
-            child: Text('清空'),
+          BackendStatusIcon(onRetry: _load),
+          ValueListenableBuilder<BackendAvailability>(
+            valueListenable: ApiClient.availability,
+            builder: (context, availability, _) => TextButton(
+              onPressed:
+                  _items.isEmpty || availability != BackendAvailability.online
+                  ? null
+                  : _clear,
+              child: Text('清空'),
+            ),
           ),
         ],
       ),