重构作业结构：优化实体模型、DTO映射和前端界面

- 重构AppMainStruct、AssignmentQuestion、Question等实体模型
- 更新相关DTO以匹配新的数据结构
- 优化前端页面布局和组件
- 添加全局信息和笔记功能相关代码
- 更新数据库迁移和程序配置

TechHelper.Client/Pages/Exam/ExamView/ExamStructView.razor

@@ -1,5 +1,6 @@
 @using Entities.Contracts
 @using Entities.DTO
+@using Newtonsoft.Json
 @using TechHelper.Client.Exam
 @using TechHelper.Client.Pages.Exam.QuestionCard
 
@@ -22,6 +23,11 @@
 				<MudIconButton Color="Color.Tertiary" Icon="@Icons.Material.Filled.ExpandMore" Size="Size.Small" />
 				<MudIconButton Icon="@Icons.Material.Filled.Delete" aria-label="delete" Size="Size.Small" />
 				<MudChip T="string" Color="Color.Info" Class="justify-content-end">@ExamStruct.StructType</MudChip>
+				<MudChip T="string" Color="Color.Warning" Class="justify-content-end">@(ExamStruct.QType == string.Empty ? "" : QuestionTypes[ExamStruct.QType].DisplayName)</MudChip>
+				@if(ExamStruct.Question!=null)
+				{
+					<MudRating SelectedValue="@((int)ExamStruct.Question.DifficultyLevel)" ReadOnly="true" Size="Size.Small" />
+				}
 			</MudStack>
 		</MudStack>
 
@@ -75,6 +81,22 @@
 	[Parameter]
 	public string Style { get; set; } = "background-color : #eeeeee";
 
+	Dictionary<string, QuestionDisplayTypeData> QuestionTypes = new Dictionary<string, QuestionDisplayTypeData>();
+
+	[Inject]
+	private ILocalStorageService LocalStorageService { get; set; }
+	protected override void OnInitialized()
+	{
+		base.OnInitialized();
+
+		var cs = LocalStorageService.GetItem<string>("GlobalInfo");
+		var GlobalInfo = JsonConvert.DeserializeObject<Dictionary<string, QuestionDisplayTypeData>>(cs);
+		if (GlobalInfo != null)
+		{
+			QuestionTypes = GlobalInfo;
+		}
+	}
+
 	private async void HandleClick()
 	{
 		await ClickedStruct.InvokeAsync(ExamStruct);
@@ -84,4 +106,10 @@
 	{
 		await ClickedStruct.InvokeAsync(clickedChildExamStruct);
 	}
+
+	private void HandleSelected(int num)
+	{
+		ExamStruct.Question.DifficultyLevel = (DifficultyLevel)num;
+	}
+
 }