fix: remove api/ prefix from Sprint 4 controllers — global prefix already set

src/achievement/achievement.controller.ts

@@ -7,7 +7,7 @@ import { Repository } from 'typeorm';
 import { Character } from '../character/entities/character.entity';
 import { BadRequestException } from '@nestjs/common';
 
-@Controller('api/achievements')
+@Controller('achievements')
 export class AchievementController {
   constructor(
     private readonly achievementService: AchievementService,