重构项目结构，移除Assignment相关功能，优化Submission模块

TechHelper.Client/Pages/Teacher/StudentsView.razor

@@ -16,7 +16,7 @@
 	[CascadingParameter]
 	private Task<AuthenticationState> authenticationStateTask { get; set; }
 
-	private List<StudentDto> ClassStudents { get; set; } = new List<StudentDto>();
+	private List<StudentExamDetailDto> ClassStudents { get; set; } = new List<StudentExamDetailDto>();
 
 	[Inject]
 	public IClassServices ClassServices { get; set; }
@@ -24,7 +24,7 @@
 	protected override async Task OnInitializedAsync()
 	{
 		var result = await ClassServices.GetClassStudents();
-		ClassStudents = result.Result as List<StudentDto> ?? new List<StudentDto>();
+		ClassStudents = result.Result as List<StudentExamDetailDto> ?? new List<StudentExamDetailDto>();
 		StateHasChanged();
 	}
 }