feat: implement QuestionBank CRUD with pagination and template query

- Add pagination support to findAll (page, limit query params)
- Add findByTemplateId method to service
- Add GET /by-template/:templateId endpoint to controller
- Service already includes CRUD for QuestionBank and QuestionBankItem

server/src/assessment/entities/question-bank.entity.ts

@@ -0,0 +1,80 @@
+import {
+  Entity,
+  PrimaryGeneratedColumn,
+  Column,
+  CreateDateColumn,
+  UpdateDateColumn,
+  ManyToOne,
+  OneToOne,
+  JoinColumn,
+  OneToMany,
+  Unique,
+} from 'typeorm';
+import { Tenant } from '../../tenant/tenant.entity';
+import { AssessmentTemplate } from './assessment-template.entity';
+import type { QuestionBankItem } from './question-bank-item.entity';
+
+export enum QuestionBankStatus {
+  DRAFT = 'DRAFT',
+  PENDING_REVIEW = 'PENDING_REVIEW',
+  PUBLISHED = 'PUBLISHED',
+  REJECTED = 'REJECTED',
+}
+
+@Entity('question_banks')
+@Unique(['templateId'])
+export class QuestionBank {
+  @PrimaryGeneratedColumn('uuid')
+  id: string;
+
+  @Column({ name: 'tenant_id', nullable: true })
+  tenantId: string | null;
+
+  @ManyToOne(() => Tenant, { nullable: true, onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'tenant_id' })
+  tenant: Tenant;
+
+  @Column({ name: 'template_id', nullable: true })
+  templateId: string | null;
+
+  @OneToOne(() => AssessmentTemplate, { nullable: true })
+  @JoinColumn({ name: 'template_id' })
+  template: AssessmentTemplate;
+
+  @Column()
+  name: string;
+
+  @Column({ type: 'text', nullable: true })
+  description: string | null;
+
+  @Column({
+    type: 'enum',
+    enum: QuestionBankStatus,
+    default: QuestionBankStatus.DRAFT,
+  })
+  status: QuestionBankStatus;
+
+  @Column({ name: 'created_by', nullable: true })
+  createdBy: string | null;
+
+  @Column({ name: 'reviewed_by', nullable: true })
+  reviewedBy: string | null;
+
+  @Column({ name: 'reviewed_at', nullable: true })
+  reviewedAt: Date | null;
+
+  @Column({ name: 'review_comment', nullable: true })
+  reviewComment: string | null;
+
+  @OneToMany(
+    'QuestionBankItem',
+    (item: QuestionBankItem) => item.bank,
+  )
+  items: QuestionBankItem[];
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt: Date;
+
+  @UpdateDateColumn({ name: 'updated_at' })
+  updatedAt: Date;
+}