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/dto/create-template.dto.ts

@@ -0,0 +1,94 @@
+import {
+  IsString,
+  IsNotEmpty,
+  IsOptional,
+  IsArray,
+  IsInt,
+  Min,
+  Max,
+  IsObject,
+  IsBoolean,
+} from 'class-validator';
+
+export class CreateTemplateDto {
+  @IsString()
+  @IsNotEmpty()
+  name: string;
+
+  @IsString()
+  @IsOptional()
+  description?: string;
+
+  @IsArray()
+  @IsString({ each: true })
+  @IsOptional()
+  keywords?: string[];
+
+  @IsInt()
+  @Min(1)
+  @Max(20)
+  @IsOptional()
+  questionCount?: number = 5;
+
+  @IsObject()
+  @IsOptional()
+  difficultyDistribution?: {
+    standard: number;
+    advanced: number;
+    specialist: number;
+  };
+
+  @IsString()
+  @IsOptional()
+  style?: string = 'technical';
+
+  @IsString()
+  @IsOptional()
+  knowledgeBaseId?: string;
+
+  @IsString()
+  @IsOptional()
+  knowledgeGroupId?: string;
+
+  @IsBoolean()
+  @IsOptional()
+  isActive?: boolean = true;
+
+  @IsArray()
+  @IsString({ each: true })
+  @IsOptional()
+  linkedGroupIds?: string[];
+
+  @IsObject()
+  @IsOptional()
+  weightConfig?: {
+    prompt: number;
+    other: number;
+  };
+
+  @IsObject()
+  @IsOptional()
+  difficultyConfig?: {
+    standard: number;
+    advanced: number;
+    specialist: number;
+  };
+
+  @IsInt()
+  @Min(1)
+  @Max(20)
+  @IsOptional()
+  questionCountMin?: number;
+
+  @IsInt()
+  @Min(1)
+  @Max(20)
+  @IsOptional()
+  questionCountMax?: number;
+
+  @IsInt()
+  @Min(0)
+  @Max(100)
+  @IsOptional()
+  passingScore?: number;
+}

server/src/assessment/dto/update-template.dto.ts

@@ -0,0 +1,4 @@
+import { PartialType } from '@nestjs/mapped-types';
+import { CreateTemplateDto } from './create-template.dto';
+
+export class UpdateTemplateDto extends PartialType(CreateTemplateDto) {}