refactor: 重构项目目录与代码结构，清理冗余文件

本次提交进行了大规模的项目结构调整：
1. 调整文件目录归属，将模块代码按功能域重新组织
2. 删除多处冗余的DTO、实体类和模块文件
3. 统一了常量、装饰器、工具类的存放位置
4. 修复了`.gitignore`的日志目录匹配规则
5. 新增了健康检查、认证、用户、剧集、订单等核心业务模块

middleware/request-id.middleware.ts

@@ -0,0 +1,21 @@
+import { NextFunction, Request, Response } from 'express';
+import { validate as validateUuid, version as uuidVersion, v4 as uuidv4 } from 'uuid';
+
+export function RequestIdMiddleware(
+  request: Request & { requestId?: string; startTime?: bigint },
+  response: Response,
+  next: NextFunction,
+) {
+  const incomingRequestId = request.get('x-request-id');
+  const requestId =
+    incomingRequestId &&
+    validateUuid(incomingRequestId) &&
+    uuidVersion(incomingRequestId) === 4
+      ? incomingRequestId
+      : uuidv4();
+
+  request.requestId = requestId;
+  request.startTime = process.hrtime.bigint();
+  response.setHeader('X-Request-Id', requestId);
+  next();
+}