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

TechHelper.Server/Controllers/CommonController.cs

@@ -0,0 +1,28 @@
+using Entities.Contracts;
+using Entities.DTO;
+using Microsoft.AspNetCore.Identity;
+using Microsoft.AspNetCore.Mvc;
+
+namespace TechHelper.Server.Controllers
+{
+	[Route("api/common")]
+	[ApiController]
+	public class CommonController : Controller
+	{
+		private readonly UserManager<User> _userManager;
+
+		public CommonController(UserManager<User> userManager)
+		{
+			_userManager = userManager;
+		}
+
+		[HttpGet("GetCommonType")]
+		public IActionResult GetCommonType(TypeCommonRequest typeCommon)
+		{
+			return Ok();
+		}
+
+
+
+	}
+}