feat: 新增剧集封面、集数管理与上传优化功能

1. 新增Cover实体类并注册到数据库模块
2. 为剧集添加总集数字段及自动创建集数槽功能
3. 新增管理员更新剧集集数接口
4. 优化发布剧集列表：支持标题过滤与默认分页大小10
5. 扩展MediaUploadJob实体字段，完善媒体上传流程
6. 重构订单与媒体服务，新增数据库持久化支持
7. 新增剧集标题过滤的端到端测试用例

src/modules/media/entities/cover.entity.ts

@@ -0,0 +1,21 @@
+import {
+  Column,
+  CreateDateColumn,
+  Entity,
+  PrimaryGeneratedColumn,
+} from 'typeorm';
+
+@Entity('covers')
+export class Cover {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @Column({ type: 'varchar', length: 255 })
+  fileName: string;
+
+  @Column({ type: 'varchar', length: 1024 })
+  url: string;
+
+  @CreateDateColumn()
+  createdAt: Date;
+}

src/modules/media/entities/media-upload-job.entity.ts

@@ -16,6 +16,9 @@ export class MediaUploadJob {
   @Column({ type: 'varchar', length: 128 })
   jobId: string;
 
+  @Column({ type: 'int', nullable: true })
+  episodeId?: number;
+
   @Index()
   @Column({ type: 'varchar', length: 128, nullable: true })
   byteplusVid?: string;
@@ -23,6 +26,42 @@ export class MediaUploadJob {
   @Column({ type: 'varchar', length: 64 })
   status: string;
 
+  @Column({ type: 'varchar', length: 255, nullable: true })
+  fileName?: string;
+
+  @Column({ type: 'varchar', length: 128, nullable: true })
+  contentType?: string;
+
+  @Column({ type: 'int', nullable: true })
+  fileSize?: number;
+
+  @Column({ type: 'varchar', length: 255, nullable: true })
+  bucket?: string;
+
+  @Column({ type: 'varchar', length: 512, nullable: true })
+  objectKey?: string;
+
+  @Column({ type: 'varchar', length: 1024, nullable: true })
+  uploadUrl?: string;
+
+  @Column({ type: 'varchar', length: 1024, nullable: true })
+  videoUrl?: string;
+
+  @Column({ type: 'int', nullable: true })
+  width?: number;
+
+  @Column({ type: 'int', nullable: true })
+  height?: number;
+
+  @Column({ type: 'int', nullable: true })
+  durationSeconds?: number;
+
+  @Column({ type: 'varchar', length: 32, nullable: true })
+  reviewStatus?: 'not_submitted' | 'pending' | 'reviewing' | 'approved' | 'rejected';
+
+  @Column({ type: 'varchar', length: 512, nullable: true })
+  reviewMessage?: string;
+
   @Column({ type: 'json', nullable: true })
   rawResponse?: Record<string, unknown>;