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/ExamGlobalInfoDialog.razor

@@ -0,0 +1,34 @@
+@using Entities.DTO
+@inject ISnackbar Snackbar
+
+<MudDialog Class="rounded-xl" Style="background-color: #dedede" >
+    <TitleContent>
+        <MudText Typo="Typo.h6">
+            <MudIcon Icon="@Icons.Material.Filled.EditAttributes" Class="mr-3 mb-n1" />
+            <b> 编辑属性 </b>
+        </MudText>
+    </TitleContent>
+    <DialogContent>
+        <GlobalInfoCard AssignmentDto="Assignment"></GlobalInfoCard>
+    </DialogContent>
+    <DialogActions>
+        <MudButton OnClick="Cancel">Cancel</MudButton>
+        <MudButton Color="Color.Error" OnClick="Confirm">确认</MudButton>
+    </DialogActions>
+</MudDialog>
+
+@code {
+    [CascadingParameter]
+    private IMudDialogInstance MudDialog { get; set; }
+
+    [Parameter]
+    public AssignmentDto Assignment { get; set; } = new AssignmentDto();
+
+    private void Cancel() => MudDialog.Cancel();
+
+    private void Confirm()
+    {
+        Snackbar.Add("属性已更新", Severity.Success);
+        MudDialog.Close(DialogResult.Ok(Assignment));
+    }
+}