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/role.entity.ts

@@ -0,0 +1,38 @@
+import { Entity, PrimaryGeneratedColumn, Column, CreateDateColumn, UpdateDateColumn, ManyToMany, JoinTable } from 'typeorm';
+import { Permission } from './permission.entity';
+import { User } from './user.entity';
+
+@Entity('roles')
+export class Role {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @Column({ type: 'varchar', length: 30, unique: true })
+  name: string;
+
+  @Column({ type: 'varchar', length: 200, nullable: true })
+  description: string;
+
+  @Column({ name: 'is_system', type: 'boolean', default: false })
+  isSystem: boolean;
+
+  @Column({ type: 'tinyint', default: 1 })
+  status: number;
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt: Date;
+
+  @UpdateDateColumn({ name: 'updated_at' })
+  updatedAt: Date;
+
+  @ManyToMany(() => Permission)
+  @JoinTable({
+    name: 'role_permissions',
+    joinColumn: { name: 'role_id', referencedColumnName: 'id' },
+    inverseJoinColumn: { name: 'permission_id', referencedColumnName: 'id' },
+  })
+  permissions: Permission[];
+
+  @ManyToMany(() => User, (user) => user.roles)
+  users: User[];
+}