feat: add Class, ClassStudent, ClassTeacher entities

apps/server/src/entities/class.entity.ts

@@ -0,0 +1,76 @@
+import {
+  Entity,
+  PrimaryGeneratedColumn,
+  Column,
+  CreateDateColumn,
+  UpdateDateColumn,
+  ManyToOne,
+  JoinColumn,
+} from 'typeorm';
+
+export enum ClassType {
+  CULTURE = 'culture',
+  PROFESSIONAL = 'professional',
+  BOOTCAMP = 'bootcamp',
+  SPRINT = 'sprint',
+}
+
+export enum ClassStatus {
+  ENROLLING = 'enrolling',
+  ACTIVE = 'active',
+  ENDED = 'ended',
+  SUSPENDED = 'suspended',
+}
+
+@Entity('classes')
+export class Class {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @Column({ name: 'name', length: 100 })
+  name: string;
+
+  @Column({ name: 'code', length: 50, unique: true })
+  code: string;
+
+  @Column({ name: 'department_id', type: 'integer', nullable: true })
+  departmentId: number;
+
+  // Forward reference — Department entity will be added later
+  @ManyToOne('Department', { nullable: true })
+  @JoinColumn({ name: 'department_id' })
+  department: unknown;
+
+  @Column({ name: 'class_type', length: 20 })
+  classType: string;
+
+  @Column({ name: 'start_date', type: 'date', nullable: true })
+  startDate: string;
+
+  @Column({ name: 'end_date', type: 'date', nullable: true })
+  endDate: string;
+
+  @Column({ name: 'status', length: 20, default: ClassStatus.ENROLLING })
+  status: string;
+
+  @Column({ name: 'head_teacher_id', type: 'integer', nullable: true })
+  headTeacherId: number;
+
+  @Column({ name: 'life_teacher_id', type: 'integer', nullable: true })
+  lifeTeacherId: number;
+
+  @Column({ name: 'academic_teacher_id', type: 'integer', nullable: true })
+  academicTeacherId: number;
+
+  @Column({ name: 'max_students', type: 'integer', default: 0 })
+  maxStudents: number;
+
+  @Column({ name: 'notes', type: 'text', nullable: true })
+  notes: string;
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt: Date;
+
+  @UpdateDateColumn({ name: 'updated_at' })
+  updatedAt: Date;
+}