feat: UI全面改造 + 后端多项修复

【后端修复】
- 删除diet/consultation agent假工具声明
- 修复DayOfWeek实体注释
- 修复Vision API content序列化
- cleanup_service级联删除修复
- 用药提醒时区偏差修复
- 统一DateTime处理(UtcNow+8)
- 新增UTC DateTime JSON转换器

【前端UI重构】
- 配色体系全面更新(#8B5CF6淡紫+#F0ECFF背景)
- 登录页重设计
- 首页重设计(透明顶栏、渐变背景、胶囊输入区)
- 聊天卡片加白蓝边框、渐变标题
- 侧边栏重构(渐变背景、合并顶部、删除底部设置)
- 确认卡片可编辑字段恢复
- 所有子页面加返回按钮
- catch异常加日志
- 删除后refresh provider缓存

backend/src/Health.Infrastructure/AI/AgentHandlers/consultation_agent_handler.cs

@@ -1,20 +1,11 @@
 namespace Health.Infrastructure.AI.AgentHandlers;
 
 /// <summary>
-/// AI 问诊 Agent 工具处理器——转医生
+/// 问诊 Agent 工具处理器（问诊转医生走专门界面，此处只保留档案和记录查询）
 /// </summary>
 public static class ConsultationAgentHandler
 {
-    public static readonly ToolDefinition RequestDoctorTool = new()
-    {
-        Function = new()
-        {
-            Name = "request_doctor", Description = "请求转接真人医生",
-            Parameters = new { type = "object", properties = new { reason = new { type = "string" }, urgency_level = new { type = "string" } } }
-        }
-    };
-
-    public static List<ToolDefinition> Tools => [CommonAgentHandler.QueryHealthRecordsTool, CommonAgentHandler.CheckArchiveTool, RequestDoctorTool];
+    public static List<ToolDefinition> Tools => [CommonAgentHandler.QueryHealthRecordsTool, CommonAgentHandler.CheckArchiveTool];
 
     public static Task<object> Execute(string toolName, JsonElement args, AppDbContext db, Guid userId)
     {

backend/src/Health.Infrastructure/AI/AgentHandlers/diet_agent_handler.cs

@@ -1,16 +1,11 @@
 namespace Health.Infrastructure.AI.AgentHandlers;
 
 /// <summary>
-/// 拍饮食 Agent 工具处理器——食物估算
+/// 饮食 Agent 工具处理器（饮食拍照走专门界面，此处只保留档案查询）
 /// </summary>
 public static class DietAgentHandler
 {
-    public static readonly ToolDefinition EstimateFoodTool = new()
-    {
-        Function = new() { Name = "estimate_food_text", Description = "根据文字描述估算食物份量和热量", Parameters = new { type = "object", properties = new { text = new { type = "string" } }, required = new[] { "text" } } }
-    };
-
-    public static List<ToolDefinition> Tools => [EstimateFoodTool, CommonAgentHandler.CheckArchiveTool];
+    public static List<ToolDefinition> Tools => [CommonAgentHandler.CheckArchiveTool];
 
     public static Task<object> Execute(string toolName, JsonElement args, AppDbContext db, Guid userId)
     {

backend/src/Health.Infrastructure/AI/AgentHandlers/exercise_agent_handler.cs

@@ -40,7 +40,7 @@ public static class ExerciseAgentHandler
         switch (action)
         {
             case "create":
-                var weekStart = args.TryGetProperty("week_start_date", out var wsd) ? DateOnly.Parse(wsd.GetString()!) : DateOnly.FromDateTime(DateTime.Now);
+                var weekStart = args.TryGetProperty("week_start_date", out var wsd) ? DateOnly.Parse(wsd.GetString()!) : DateOnly.FromDateTime(DateTime.UtcNow.AddHours(8));
                 var plan = new ExercisePlan { Id = Guid.NewGuid(), UserId = userId, WeekStartDate = weekStart };
                 if (args.TryGetProperty("items", out var items))
                 {

backend/src/Health.Infrastructure/AI/AgentHandlers/medication_agent_handler.cs

@@ -71,8 +71,8 @@ public static class MedicationAgentHandler
             Name = name, Dosage = dosage, Frequency = frequency,
             TimeOfDay = times.Count > 0 ? times : [new TimeOnly(8, 0)],
             Source = MedicationSource.AiEntry, IsActive = true,
-            StartDate = DateOnly.TryParse(startDateStr, out var parsedDate) ? parsedDate : DateOnly.FromDateTime(DateTime.Now),
-            EndDate = durationDays > 0 ? DateOnly.FromDateTime(DateTime.Now).AddDays(durationDays) : null,
+            StartDate = DateOnly.TryParse(startDateStr, out var parsedDate) ? parsedDate : DateOnly.FromDateTime(DateTime.UtcNow.AddHours(8)),
+            EndDate = durationDays > 0 ? DateOnly.FromDateTime(DateTime.UtcNow.AddHours(8)).AddDays(durationDays) : null,
         };
         db.Medications.Add(med);
         await db.SaveChangesAsync();
@@ -100,7 +100,7 @@ public static class MedicationAgentHandler
         db.MedicationLogs.Add(new MedicationLog
         {
             Id = Guid.NewGuid(), MedicationId = medId, UserId = userId,
-            Status = MedicationLogStatus.Taken, ScheduledTime = TimeOnly.FromDateTime(DateTime.Now), ConfirmedAt = DateTime.UtcNow,
+            Status = MedicationLogStatus.Taken, ScheduledTime = TimeOnly.FromDateTime(DateTime.UtcNow.AddHours(8)), ConfirmedAt = DateTime.UtcNow,
         });
         await db.SaveChangesAsync();
         return new { success = true };

backend/src/Health.Infrastructure/AI/open_ai_compatible_client.cs

@@ -133,7 +133,7 @@ public sealed class OpenAiCompatibleClient(string baseUrl, string apiKey, string
         var userMessage = new ChatMessage
         {
             Role = "user",
-            Content = JsonSerializer.Serialize(contentParts, _jsonOptions)
+            Content = contentParts  // 数组格式，让 JSON 序列化时保持为数组而非字符串
         };
 
         messages.Add(userMessage);

backend/src/Health.Infrastructure/AI/prompt_manager.cs

@@ -126,7 +126,7 @@ public sealed class PromptManager
 
         领域判断与可用工具：
         1. 健康数据（血压/心率/血糖/血氧/体重）→ 调用 record_health_data
-        2. 饮食分析 → 调用 estimate_food_text
+        2. 饮食分析 → 引导用户使用「拍饮食」功能拍照识别
         3. 用药管理 → 调用 manage_medication
         4. 运动计划 → 调用 manage_exercise
         5. 健康档案查询/修改 → 调用 check_archive / manage_archive