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/media/media.service.ts

@@ -0,0 +1,65 @@
+import { Injectable } from '@nestjs/common';
+import { PaginatedResponse } from '../../common/dto/paginated-response.dto';
+import { CreateCoverDto } from './dto/create-cover.dto';
+import { CreateUploadJobDto } from './dto/create-upload-job.dto';
+import {
+  CoverRecord,
+  MediaUploadJobRecord,
+} from './interfaces/media-records.interface';
+
+interface PaginationInput {
+  page: number;
+  pageSize: number;
+}
+
+@Injectable()
+export class MediaService {
+  private coverSequence = 1;
+  private uploadJobSequence = 1;
+  private readonly covers: CoverRecord[] = [];
+  private readonly uploadJobs: MediaUploadJobRecord[] = [];
+
+  createCover(dto: CreateCoverDto): CoverRecord {
+    const cover: CoverRecord = {
+      id: this.coverSequence++,
+      fileName: dto.fileName,
+      url: dto.url,
+      createdAt: new Date().toISOString(),
+    };
+    this.covers.push(cover);
+    return cover;
+  }
+
+  createUploadJob(dto: CreateUploadJobDto): MediaUploadJobRecord {
+    const now = new Date().toISOString();
+    const job: MediaUploadJobRecord = {
+      id: this.uploadJobSequence++,
+      jobId: dto.jobId,
+      byteplusVid: dto.byteplusVid,
+      status: dto.status,
+      rawResponse: dto.rawResponse,
+      createdAt: now,
+      updatedAt: now,
+    };
+    this.uploadJobs.push(job);
+    return job;
+  }
+
+  listUploadJobs(
+    input: PaginationInput,
+  ): PaginatedResponse<MediaUploadJobRecord> {
+    const page = Math.max(input.page, 1);
+    const pageSize = Math.min(Math.max(input.pageSize, 1), 100);
+    const start = (page - 1) * pageSize;
+    const records = [...this.uploadJobs].reverse();
+
+    return {
+      list: records.slice(start, start + pageSize),
+      pagination: {
+        page,
+        pageSize,
+        total: records.length,
+      },
+    };
+  }
+}