feat(task1): restructure directories for turborepo monorepo

- Move backend/ to apps/server/ via git mv
- Move frontend/ to apps/admin/ via git mv
- Create packages/typescript-config/ with base, nestjs, and react-vite presets

apps/server/src/entities/room-expense.entity.ts

@@ -0,0 +1,36 @@
+import { Entity, PrimaryGeneratedColumn, Column, CreateDateColumn, ManyToOne, JoinColumn } from 'typeorm';
+import { Room } from './room.entity';
+
+@Entity('room_expenses')
+export class RoomExpense {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @Column({ name: 'room_id' })
+  roomId: number;
+
+  @Column({ name: 'expense_type', type: 'varchar', length: 20 })
+  expenseType: string;
+
+  @Column({ type: 'decimal', precision: 10, scale: 2 })
+  amount: number;
+
+  @Column({ name: 'period_start', type: 'date' })
+  periodStart: string;
+
+  @Column({ name: 'period_end', type: 'date' })
+  periodEnd: string;
+
+  @Column({ type: 'text', nullable: true })
+  description: string;
+
+  @Column({ name: 'recorded_by', nullable: true })
+  recordedBy: number;
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt: Date;
+
+  @ManyToOne(() => Room, (r) => r.roomExpenses)
+  @JoinColumn({ name: 'room_id' })
+  room: Room;
+}