feat: add Notification entity

apps/server/src/entities/index.ts

@@ -22,3 +22,5 @@ export { AttendanceRecord } from './attendance-record.entity';
 export { DingAttendanceRaw } from './ding-attendance-raw.entity';
 export { SyncLog } from './sync-log.entity';
 export { SyncState } from './sync-state.entity';
+export { ExpenseType } from './expense-type.entity';
+export { Notification, NotificationType } from './notification.entity';

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

@@ -0,0 +1,55 @@
+import {
+  Entity,
+  PrimaryGeneratedColumn,
+  Column,
+  CreateDateColumn,
+  ManyToOne,
+  JoinColumn,
+} from 'typeorm';
+import { User } from './user.entity';
+
+export enum NotificationType {
+  BILL_GENERATED = 'bill_generated',
+  BILL_PAID = 'bill_paid',
+  CHECK_IN = 'check_in',
+  CHECK_OUT = 'check_out',
+  DEPOSIT_DUE = 'deposit_due',
+  DEPOSIT_REFUNDED = 'deposit_refunded',
+  CLASS_CHANGE = 'class_change',
+  SCHEDULE_CONFLICT = 'schedule_conflict',
+  ANNOUNCEMENT = 'announcement',
+}
+
+@Entity('notifications')
+export class Notification {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @Column({ name: 'recipient_id', type: 'integer' })
+  recipientId: number;
+
+  @ManyToOne(() => User, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'recipient_id' })
+  recipient: User;
+
+  @Column({ name: 'type', length: 30 })
+  type: string;
+
+  @Column({ name: 'title', length: 200 })
+  title: string;
+
+  @Column({ name: 'content', type: 'text', nullable: true })
+  content: string;
+
+  @Column({ name: 'link', length: 500, nullable: true })
+  link: string;
+
+  @Column({ name: 'is_read', type: 'boolean', default: false })
+  isRead: boolean;
+
+  @Column({ name: 'read_at', type: 'datetime', nullable: true })
+  readAt: Date;
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt: Date;
+}