feat(users): add API documentation properties to CreateUserDto using Swagger decorators

backend/src/modules/users/dto/create-user.dto.ts

@@ -1,21 +1,40 @@
 import { IsString, IsNotEmpty, IsOptional, IsObject } from 'class-validator';
+import { ApiProperty } from '@nestjs/swagger';
 
 /**
  * DTO for creating a new user
  */
 export class CreateUserDto {
+  @ApiProperty({
+    description: 'The name of the user',
+    example: 'John Doe'
+  })
   @IsString()
   @IsNotEmpty()
   name: string;
 
+  @ApiProperty({
+    description: 'The avatar URL of the user',
+    example: 'https://example.com/avatar.png',
+    required: false
+  })
   @IsString()
   @IsOptional()
   avatar?: string;
 
+  @ApiProperty({
+    description: 'The GitHub ID of the user',
+    example: 'github123456'
+  })
   @IsString()
   @IsNotEmpty()
   githubId: string;
 
+  @ApiProperty({
+    description: 'Additional metadata for the user',
+    example: { email: 'john.doe@example.com' },
+    required: false
+  })
   @IsObject()
   @IsOptional()
   metadata?: Record<string, any>;