test(frontend): #343 Jest+RTL 인프라 + ARIA Tabs + remotePatterns

테스트 인프라:
- Jest 30 + jest-environment-jsdom + RTL + jest-dom matchers
- next/jest로 SWC/Next.js 자동 통합
- jest.config.ts (setupFilesAfterEnv) + jest.setup.ts
- npm scripts: test, test:watch
- 샘플 테스트 3개, 13/13 통과:
  - i18n/config: isLocale + detectBrowserLocale (5 케이스)
  - Stars 컴포넌트: 별점/aria/clamp/showNumber (5 케이스)
  - admin-utils: getAdminToken + authHeaders (4 케이스)

ARIA Tabs (MyReviewsList):
- role=tablist + tab + aria-selected + aria-controls + tabIndex
- panel에 role=tabpanel + aria-labelledby

next/image:
- next.config.ts remotePatterns: lh3.googleusercontent.com / i.ytimg.com / yt3.ggpht.com
- ReviewSection의 user_avatar_url에 명시적 eslint-disable + 사유

후속(별도): 전체 컴포넌트 테스트 점진 추가, 백엔드 JUnit 인프라, E2E (Playwright), CI 통합

설계서: docs/design/343-frontend-test-infra/README.md

Refs: #343

frontend/package.json

@@ -6,7 +6,9 @@
     "dev": "next dev",
     "build": "next build",
     "start": "next start",
-    "lint": "eslint"
+    "lint": "eslint",
+    "test": "jest",
+    "test:watch": "jest --watch"
   },
   "dependencies": {
     "@phosphor-icons/react": "^2.1.10",
@@ -22,11 +24,17 @@
   },
   "devDependencies": {
     "@tailwindcss/postcss": "^4",
+    "@testing-library/jest-dom": "^6.9.1",
+    "@testing-library/react": "^16.3.2",
+    "@testing-library/user-event": "^14.6.1",
+    "@types/jest": "^30.0.0",
     "@types/node": "^20",
     "@types/react": "^19",
     "@types/react-dom": "^19",
     "eslint": "^9",
     "eslint-config-next": "16.1.6",
+    "jest": "^30.4.2",
+    "jest-environment-jsdom": "^30.4.1",
     "tailwindcss": "^4",
     "typescript": "^5"
   }