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/constants.ts

@@ -29,8 +29,6 @@ export const CACHE_TTL = {
   HEALTH: 30,
   /** Cache TTL for pricing data (1 hour) */
   PRICING: 3600,
-  /** Cache TTL for recommendation results (10 minutes) */
-  RECOMMENDATIONS: 600,
   /** Default cache TTL (5 minutes) */
   DEFAULT: 300,
 } as const;
@@ -61,8 +59,6 @@ export const RATE_LIMIT_DEFAULTS = {
   MAX_REQUESTS_INSTANCES: 100,
   /** Maximum requests per window for /sync endpoint */
   MAX_REQUESTS_SYNC: 10,
-  /** Maximum requests per window for /recommend endpoint */
-  MAX_REQUESTS_RECOMMEND: 50,
 } as const;
 
 // ============================================================