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

TechHelper.Server/Repository/ExamQuestionRepository.cs

@@ -0,0 +1,14 @@
+using Entities.Contracts;
+using Microsoft.EntityFrameworkCore;
+using SharedDATA.Api;
+using TechHelper.Context;
+
+namespace TechHelper.Repository
+{
+    public class ExamQuestionRepository : Repository<ExamQuestion>, IRepository<ExamQuestion>
+    {
+        public ExamQuestionRepository(ApplicationContext dbContext) : base(dbContext)
+        {
+        }
+    }
+}