fix: add build script for server, fix duplicate index in user_ding_mapping entity

apps/server/src/entities/user-ding-mapping.entity.ts

@@ -0,0 +1,52 @@
+import {
+  Entity,
+  PrimaryGeneratedColumn,
+  Column,
+  CreateDateColumn,
+  UpdateDateColumn,
+  Index,
+  ManyToOne,
+  JoinColumn,
+} from 'typeorm';
+import { User } from './user.entity';
+
+/**
+ * Maps DingTalk user IDs to local User records.
+ * Used for incremental sync and attendance auto-matching.
+ *
+ * Mapping chain:
+ *   dingtalk userid → UserDingMapping.dingUserId → UserDingMapping.userId
+ *   → User.id → Student.userId → Student.id
+ *   → DingAttendanceRaw.dingUserId → UserDingMapping.dingUserId → auto-match
+ */
+@Entity('user_ding_mapping')
+export class UserDingMapping {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  /** DingTalk user ID (from DingTalk API) */
+  @Column({ name: 'ding_user_id', length: 100, unique: true })
+  dingUserId: string;
+
+  /** Local User ID */
+  @Column({ name: 'user_id', type: 'integer', unique: true })
+  userId: number;
+
+  @ManyToOne(() => User, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'user_id' })
+  user: User;
+
+  /** DingTalk user name (cached for display) */
+  @Column({ name: 'ding_name', length: 100, nullable: true })
+  dingName: string;
+
+  /** DingTalk mobile (cached for display) */
+  @Column({ name: 'ding_mobile', length: 20, nullable: true })
+  dingMobile: string;
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt: Date;
+
+  @UpdateDateColumn({ name: 'updated_at' })
+  updatedAt: Date;
+}