chore: 初始化TikTok短剧后端项目基础架构

创建了完整的NestJS项目结构，包含配置文件、核心模块、工具类、拦截器、过滤器等基础代码，实现了健康检查、用户认证、管理员RBAC、剧集管理、订单支付、媒体管理等核心功能的基础框架，配置了ESLint、TypeScript、Jest等开发工具链。

src/modules/auth/guards/jwt-auth.guard.ts

@@ -0,0 +1,42 @@
+import {
+  CanActivate,
+  ExecutionContext,
+  Injectable,
+  UnauthorizedException,
+} from '@nestjs/common';
+import { JwtService } from '@nestjs/jwt';
+import { Request } from 'express';
+import { UsersService } from '../../users/users.service';
+
+@Injectable()
+export class JwtAuthGuard implements CanActivate {
+  constructor(
+    private readonly jwtService: JwtService,
+    private readonly usersService: UsersService,
+  ) {}
+
+  async canActivate(context: ExecutionContext): Promise<boolean> {
+    const request = context.switchToHttp().getRequest<Request & { user?: unknown }>();
+    const authHeader = request.get('authorization');
+    const token = authHeader?.startsWith('Bearer ')
+      ? authHeader.slice('Bearer '.length)
+      : undefined;
+
+    if (!token) {
+      throw new UnauthorizedException('Not authenticated');
+    }
+
+    try {
+      const payload = await this.jwtService.verifyAsync<{ sub: number }>(token);
+      const user = this.usersService.findById(payload.sub);
+      if (!user || user.status !== 'active') {
+        throw new UnauthorizedException('Not authenticated');
+      }
+
+      request.user = user;
+      return true;
+    } catch {
+      throw new UnauthorizedException('Not authenticated');
+    }
+  }
+}