feat: 用药打卡全面重构 - 按次追踪 + 独立打卡页 + 任务区汇总

- 后端用药提醒改为按次粒度(每个服药时间独立判断)
- 新增 per-dose 打卡/取消打卡 API
- 新增 MedicationCheckInPage 独立打卡页(每药每时间单独toggle)
- 用药列表删底部弹窗(编辑/停药),点药品直接进该药打卡页
- 任务区用药汇总为一行(过期待服已服)
- 支持隔天(EveryOtherDay)/每周频率判断
- 删历史对话功能(ConversationItem + conversationListProvider + UI)

health_app/lib/providers/chat_provider.dart

@@ -13,7 +13,7 @@ class ChatMessage {
   String content;
   final DateTime createdAt;
   MessageType type;
-  final Map<String, dynamic>? metadata;
+  Map<String, dynamic>? metadata;
   bool confirmed;
   ChatMessage({
     required this.id,
@@ -53,22 +53,6 @@ class ChatState {
       );
 }
 
-class ConversationItem {
-  final String id;
-  final String title;
-  final String lastMessage;
-  final DateTime updatedAt;
-  final ActiveAgent agent;
-
-  ConversationItem({
-    required this.id,
-    required this.title,
-    required this.lastMessage,
-    required this.updatedAt,
-    required this.agent,
-  });
-}
-
 class SelectedAgentNotifier extends Notifier<ActiveAgent?> {
   @override
   ActiveAgent? build() => null;
@@ -78,28 +62,6 @@ class SelectedAgentNotifier extends Notifier<ActiveAgent?> {
 final selectedAgentProvider =
     NotifierProvider<SelectedAgentNotifier, ActiveAgent?>(SelectedAgentNotifier.new);
 final chatProvider = NotifierProvider<ChatNotifier, ChatState>(ChatNotifier.new);
-final conversationListProvider = FutureProvider<List<ConversationItem>>((ref) async {
-  final api = ref.watch(apiClientProvider);
-  final token = await api.accessToken;
-  if (token == null) return [];
-  
-  try {
-    final res = await api.get('/api/ai/conversations');
-    final list = res.data['data'] as List? ?? [];
-    return list.map((item) {
-      final data = item as Map<String, dynamic>;
-      return ConversationItem(
-        id: data['id']?.toString() ?? '',
-        title: data['title']?.toString() ?? '对话',
-        lastMessage: data['lastMessage']?.toString() ?? '',
-        updatedAt: DateTime.parse(data['updatedAt']?.toString() ?? DateTime.now().toIso8601String()),
-        agent: _parseAgent(data['agentType']?.toString()),
-      );
-    }).toList();
-  } catch (_) {
-    return [];
-  }
-});
 
 ActiveAgent _parseAgent(String? type) {
   switch (type?.toLowerCase()) {
@@ -138,6 +100,8 @@ class ChatNotifier extends Notifier<ChatState> {
   }
 
   void setAgent(ActiveAgent a) {
+    // 流式回复中忽略胶囊切换，防止状态混乱
+    if (state.isStreaming) return;
     _subscription?.cancel();
     state = state.copyWith(activeAgent: a);
     ref.read(selectedAgentProvider.notifier).select(a);
@@ -190,16 +154,12 @@ class ChatNotifier extends Notifier<ChatState> {
         );
       }).toList();
 
-      // 从对话列表中找到对应的 agent 类型
-      final convList = ref.read(conversationListProvider).value ?? [];
-      final conv = convList.firstWhere((c) => c.id == convId, orElse: () => ConversationItem(id: convId, title: '', lastMessage: '', updatedAt: DateTime.now(), agent: ActiveAgent.default_));
-
       state = state.copyWith(
         messages: messages,
         conversationId: convId,
-        activeAgent: conv.agent,
+        activeAgent: ActiveAgent.default_,
       );
-      ref.read(selectedAgentProvider.notifier).select(conv.agent);
+      ref.read(selectedAgentProvider.notifier).select(ActiveAgent.default_);
     } catch (_) {}
   }
 
@@ -331,6 +291,10 @@ class ChatNotifier extends Notifier<ChatState> {
         aiMsg.content += (j['data'] as String?) ?? '';
         final messageType = j['type'] as String? ?? 'text';
         aiMsg.type = _parseMessageType(messageType);
+        // 从 SSE 中获取元数据（用药/健康数据的确认信息）
+        if (j['metadata'] is Map) {
+          aiMsg.metadata = Map<String, dynamic>.from(j['metadata']);
+        }
         state = state.copyWith(thinkingText: null);
         _update(aiMsg);
       case 'notice':