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/widgets/drawer_shell.dart

@@ -3,8 +3,14 @@ import 'package:flutter/material.dart';
 class DrawerShell extends StatelessWidget {
   final double widthFactor;
   final Widget child;
+  final bool showBackground;
 
-  const DrawerShell({super.key, required this.child, this.widthFactor = 0.84});
+  const DrawerShell({
+    super.key,
+    required this.child,
+    this.widthFactor = 0.84,
+    this.showBackground = true,
+  });
 
   @override
   Widget build(BuildContext context) {
@@ -16,29 +22,32 @@ class DrawerShell extends StatelessWidget {
         borderRadius: const BorderRadius.horizontal(right: Radius.circular(28)),
         child: Stack(
           children: [
-            Positioned.fill(
-              child: Image.asset(
-                'assets/branding/drawer_background_v1.png',
-                fit: BoxFit.cover,
-                alignment: Alignment.centerLeft,
+            if (showBackground) ...[
+              Positioned.fill(
+                child: Image.asset(
+                  'assets/branding/drawer_background_v1.png',
+                  fit: BoxFit.cover,
+                  alignment: Alignment.centerLeft,
+                ),
               ),
-            ),
-            Positioned.fill(
-              child: DecoratedBox(
-                decoration: BoxDecoration(
-                  gradient: LinearGradient(
-                    begin: Alignment.topCenter,
-                    end: Alignment.bottomCenter,
-                    colors: [
-                      Colors.white.withValues(alpha: 0.12),
-                      Colors.white.withValues(alpha: 0.42),
-                      Colors.white.withValues(alpha: 0.72),
-                    ],
-                    stops: const [0.0, 0.48, 1.0],
+              Positioned.fill(
+                child: DecoratedBox(
+                  decoration: BoxDecoration(
+                    gradient: LinearGradient(
+                      begin: Alignment.topCenter,
+                      end: Alignment.bottomCenter,
+                      colors: [
+                        Colors.white.withValues(alpha: 0.12),
+                        Colors.white.withValues(alpha: 0.42),
+                        Colors.white.withValues(alpha: 0.72),
+                      ],
+                      stops: const [0.0, 0.48, 1.0],
+                    ),
                   ),
                 ),
               ),
-            ),
+            ] else
+              const Positioned.fill(child: ColoredBox(color: Colors.white)),
             child,
           ],
         ),