feat(center): add audit logs for auth and node operations

Fabric.Backend.Center/src/entities/audit-log.entity.ts

@@ -0,0 +1,25 @@
+import { Column, CreateDateColumn, Entity, PrimaryGeneratedColumn } from 'typeorm';
+
+@Entity('audit_logs')
+export class AuditLog {
+  @PrimaryGeneratedColumn('uuid')
+  id!: string;
+
+  @Column()
+  action!: string;
+
+  @Column({ nullable: true })
+  actorId!: string | null;
+
+  @Column({ nullable: true })
+  targetType!: string | null;
+
+  @Column({ nullable: true })
+  targetId!: string | null;
+
+  @Column({ type: 'text', nullable: true })
+  detail!: string | null;
+
+  @CreateDateColumn()
+  createdAt!: Date;
+}