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/Common/GlobalInfoCard.razor

@@ -0,0 +1,37 @@
+@using Entities.DTO
+@using Entities.Contracts
+@using Helper
+
+<MudPaper Elevation=5 Class="w-100 pa-5 rounded-xl" Height="@Height" Style="@Style">
+	<MudTextField Value="@AssignmentDto.Title"></MudTextField>
+	<MudTextField Value="@AssignmentDto.Score">SCORE</MudTextField>
+	<MudTextField Value="@AssignmentDto.TotalQuestions">NUMQUESTION</MudTextField>
+	<MudChipSet T="SubjectAreaEnum" SelectedValue="@AssignmentDto.SubjectArea" CheckMark SelectionMode="SelectionMode.SingleSelection" SelectedValueChanged="HandleQTSelectedValueChanged">
+
+		@foreach (SubjectAreaEnum item in Enum.GetValues(typeof(SubjectAreaEnum)))
+		{
+			var color = Helper.GetColorFromInt((int)item);
+			<MudChip Color=@color
+					 Value="@item">
+		</MudChip>
+				}
+	</MudChipSet>
+	<MudText>DUETIME</MudText>
+	<MudText>EXAMTYPE</MudText>
+</MudPaper>
+
+
+@code {
+	[Parameter]
+
+	public AssignmentDto AssignmentDto { get; set; }
+	[Parameter]
+	public string Style { get; set; }
+	[Parameter]
+	public string Height { get; set; } = "auto";
+
+	public void HandleQTSelectedValueChanged(SubjectAreaEnum subject)
+	{
+		AssignmentDto.SubjectArea = subject;
+	}
+}