feat: 添加起卦教程首次访问追踪和Agent时间上下文

- 后端 ProfileSettingsV1 添加 DivinationTutorialSettings 字段
- 前端三个起卦页面添加首次访问检测，自动弹出教程
- 教程展示后更新 settings 标记，避免重复弹出
- 使用本地状态管理避免并发更新覆盖问题
- Agent 系统提示添加时间上下文信息

backend/src/schemas/shared/user.py

@@ -46,11 +46,20 @@ class NotificationSettings(BaseModel):
     allow_vibration: bool = True
 
 
+class DivinationTutorialSettings(BaseModel):
+    divination_entry_shown: bool = False
+    auto_divination_shown: bool = False
+    manual_divination_shown: bool = False
+
+
 class ProfileSettingsV1(BaseModel):
     version: Literal[1] = 1
     preferences: PreferenceSettings = Field(default_factory=PreferenceSettings)
     privacy: dict[str, object] = Field(default_factory=dict)
     notification: NotificationSettings = Field(default_factory=NotificationSettings)
+    divination_tutorial: DivinationTutorialSettings = Field(
+        default_factory=DivinationTutorialSettings
+    )
 
 
 ProfileSettingsUnion = ProfileSettingsV1