refactor: 추천 시스템 제거

삭제된 파일:
- src/routes/recommend.ts
- src/services/recommendation.ts
- src/services/recommendation.test.ts
- src/services/stackConfig.ts
- src/services/regionFilter.ts

수정된 파일:
- src/index.ts: /recommend 라우트 제거
- src/routes/index.ts: handleRecommend export 제거
- src/constants.ts: RECOMMENDATIONS TTL, rate limit 제거
- src/middleware/rateLimit.ts: /recommend 설정 제거
- src/types.ts: 추천 관련 타입 제거
- scripts/e2e-tester.ts: recommend 시나리오 제거
- scripts/api-tester.ts: recommend 테스트 제거

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/middleware/rateLimit.ts

@@ -67,10 +67,6 @@ const RATE_LIMITS: Record<string, RateLimitConfig> = {
     maxRequests: RATE_LIMIT_DEFAULTS.MAX_REQUESTS_SYNC,
     windowMs: RATE_LIMIT_DEFAULTS.WINDOW_MS,
   },
-  '/recommend': {
-    maxRequests: RATE_LIMIT_DEFAULTS.MAX_REQUESTS_RECOMMEND,
-    windowMs: RATE_LIMIT_DEFAULTS.WINDOW_MS,
-  },
 };
 
 /**