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.entity.ts

@@ -0,0 +1,39 @@
+import { Entity, PrimaryGeneratedColumn, Column, CreateDateColumn, OneToMany } from 'typeorm';
+import { Occupancy } from './occupancy.entity';
+import { RoomExpense } from './room-expense.entity';
+
+@Entity('rooms')
+export class Room {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @Column({ name: 'room_number', length: 20, unique: true })
+  roomNumber: string;
+
+  @Column({ length: 50, nullable: true })
+  building: string;
+
+  @Column({ nullable: true })
+  floor: number;
+
+  @Column()
+  capacity: number;
+
+  @Column({ type: 'varchar', length: 20, default: 'available' })
+  status: string;
+
+  @Column({ name: 'room_type', length: 20, nullable: true })
+  roomType: string;
+
+  @Column({ length: 10, nullable: true })
+  gender: string;
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt: Date;
+
+  @OneToMany(() => Occupancy, (o) => o.room)
+  occupancies: Occupancy[];
+
+  @OneToMany(() => RoomExpense, (e) => e.room)
+  roomExpenses: RoomExpense[];
+}