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

backend/src/Health.Application/Exercises/ExerciseService.cs

@@ -41,26 +41,6 @@ public sealed class ExerciseService(IExerciseRepository exercises) : IExerciseSe
         return plan.Id;
     }
 
-    public async Task<Guid> CreateFromItemsAsync(Guid userId, DateOnly startDate, DateOnly endDate, TimeOnly? reminderTime, IReadOnlyList<ExercisePlanItemInput> items, CancellationToken ct)
-    {
-        foreach (var item in items)
-            ValidateDuration(item.DurationMinutes);
-
-        var normalizedEnd = endDate < startDate ? startDate : endDate;
-        var plan = NewPlan(userId, startDate, normalizedEnd, reminderTime);
-        foreach (var item in items.Where(x => x.ScheduledDate >= startDate && x.ScheduledDate <= normalizedEnd).GroupBy(x => x.ScheduledDate).Select(x => x.First()))
-        {
-            plan.Items.Add(new ExercisePlanItem
-            {
-                Id = Guid.NewGuid(), ScheduledDate = item.ScheduledDate,
-                ExerciseType = string.IsNullOrWhiteSpace(item.ExerciseType) ? "散步" : item.ExerciseType.Trim(),
-                DurationMinutes = item.DurationMinutes > 0 ? item.DurationMinutes : 30,
-                IsRestDay = item.IsRestDay,
-            });
-        }
-        await SaveNewAsync(plan, ct);
-        return plan.Id;
-    }
 
     // 时长上限校验：下限交由各方法兜底为 30，这里只拦截不合理的超大值
     private static void ValidateDuration(int durationMinutes)