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

interceptor/response.interceptor.ts

@@ -0,0 +1,39 @@
+import {
+  CallHandler,
+  ExecutionContext,
+  Injectable,
+  NestInterceptor,
+} from '@nestjs/common';
+import { Reflector } from '@nestjs/core';
+import { Request } from 'express';
+import { map, Observable } from 'rxjs';
+import { SUCCESS_MESSAGE } from '../constants/response-message.constants';
+import {
+  API_MESSAGE_METADATA,
+} from '../decorators/api-message.decorator';
+import { getRequestCost } from '../utils/request-context.util';
+
+@Injectable()
+export class ResponseInterceptor implements NestInterceptor {
+  constructor(private readonly reflector = new Reflector()) {}
+
+  intercept(context: ExecutionContext, next: CallHandler): Observable<unknown> {
+    const request = context
+      .switchToHttp()
+      .getRequest<Request & { requestId?: string }>();
+    const message =
+      this.reflector.get<string>(API_MESSAGE_METADATA, context.getHandler()) ??
+      SUCCESS_MESSAGE;
+
+    return next.handle().pipe(
+      map((data) => ({
+        code: 0,
+        data: data ?? {},
+        message,
+        timestamp: Date.now(),
+        requestId: request.requestId,
+        cost: `${getRequestCost(request)}ms`,
+      })),
+    );
+  }
+}