refactor: 死代码清理 + 趋势图重构 + 侧边栏交互优化 + 智能体卡片去延迟

- 死代码清理: 删除 AppCard/AppMenuItem/AppTabChip/AppButtons 等 4 个未使用 Widget 文件; 清理 common_widgets/enterprise_widgets/app_status_badge 中未使用 class; 移除 HealthService 等未使用方法; 后端移除 ExerciseService.CreateFromItemsAsync/HealthArchiveService.GetOrCreateAsync/MedicationAgentHandler 死分支/ChatRequest DTO
- 趋势图: 直线折线 + 渐变填充 + 阴影; 去网格; X 轴日+月份; Y 轴整数刻度最多 4 个; 点击数据点/录入记录显示上方浮层; 选中点变实心
- 侧边栏: 对话记录改单选删除(灰底高亮); 操作栏浮层修复触摸问题; 常用功能/健康仪表盘间距收紧; _Panel 去外框
- 智能体: 欢迎卡片去掉 400ms 延迟; 胶囊去阴影
- 其他: api_client IP 适配; 多页面 UI 微调; 新增 chat_provider/prelaunch_guardrails 测试

health_app/lib/providers/conversation_history_provider.dart

@@ -24,7 +24,8 @@ class ConversationListItem {
         title: json['title']?.toString(),
         summary: json['summary']?.toString(),
         messageCount: (json['messageCount'] as num?)?.toInt() ?? 0,
-        updatedAt: DateTime.tryParse(json['updatedAt']?.toString() ?? '') ??
+        updatedAt:
+            DateTime.tryParse(json['updatedAt']?.toString() ?? '') ??
             DateTime.now(),
       );
 }
@@ -33,15 +34,20 @@ class ConversationListItem {
 class ConversationHistoryNotifier
     extends AsyncNotifier<List<ConversationListItem>> {
   @override
-  Future<List<ConversationListItem>> build() => _fetch();
+  Future<List<ConversationListItem>> build() {
+    ref.watch(chatProvider.select((state) => state.conversationId));
+    return _fetch();
+  }
 
   Future<List<ConversationListItem>> _fetch() async {
     final api = ref.read(apiClientProvider);
     final res = await api.get('/api/ai/conversations');
     final raw = (res.data['data'] as List?) ?? const [];
+    final currentConversationId = ref.read(chatProvider).conversationId;
     return raw
         .whereType<Map>()
         .map((m) => ConversationListItem.fromJson(Map<String, dynamic>.from(m)))
+        .where((item) => item.id != currentConversationId)
         .toList();
   }
 
@@ -79,7 +85,8 @@ class ConversationHistoryNotifier
   }
 }
 
-final conversationHistoryProvider = AsyncNotifierProvider<
-    ConversationHistoryNotifier, List<ConversationListItem>>(
-  ConversationHistoryNotifier.new,
-);
+final conversationHistoryProvider =
+    AsyncNotifierProvider<
+      ConversationHistoryNotifier,
+      List<ConversationListItem>
+    >(ConversationHistoryNotifier.new);