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/operation-log.entity.ts

@@ -0,0 +1,40 @@
+import { Entity, PrimaryGeneratedColumn, Column, CreateDateColumn } from 'typeorm';
+
+@Entity('operation_logs')
+export class OperationLog {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @Column({ name: 'user_id', nullable: true })
+  userId: number;
+
+  @Column({ length: 50, nullable: true })
+  username: string;
+
+  @Column({ length: 50 })
+  module: string;
+
+  @Column({ length: 50 })
+  action: string;
+
+  @Column({ name: 'target_id', nullable: true })
+  targetId: number;
+
+  @Column({ name: 'target_type', length: 50, nullable: true })
+  targetType: string;
+
+  @Column({ type: 'text', nullable: true })
+  detail: string;
+
+  @Column({ name: 'ip_address', length: 50, nullable: true })
+  ipAddress: string;
+
+  @Column({ name: 'user_agent', length: 500, nullable: true })
+  userAgent: string;
+
+  @Column({ name: 'status', length: 20, nullable: true, default: 'success' })
+  status: string;
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt: Date;
+}