feat: 웹사이트 표준화 검사 도구 구현

- 4개 검사 엔진: HTML/CSS, 접근성(WCAG), SEO, 성능/보안 (총 50개 항목)
- FastAPI 백엔드 (9개 API, SSE 실시간 진행, PDF/JSON 리포트)
- Next.js 15 프론트엔드 (6개 페이지, 29개 컴포넌트, 반원 게이지 차트)
- Docker Compose 배포 (Backend:8011, Frontend:3011, MongoDB:27022, Redis:6392)
- 전체 테스트 32/32 PASS

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/Dockerfile

@@ -0,0 +1,48 @@
+# ==========================================
+# Stage 1: Install dependencies
+# ==========================================
+FROM node:20-alpine AS deps
+WORKDIR /app
+
+COPY package.json package-lock.json* ./
+RUN npm ci --legacy-peer-deps
+
+# ==========================================
+# Stage 2: Build the application
+# ==========================================
+FROM node:20-alpine AS builder
+WORKDIR /app
+
+COPY --from=deps /app/node_modules ./node_modules
+COPY . .
+
+ENV NEXT_TELEMETRY_DISABLED=1
+ENV NEXT_PUBLIC_API_URL=http://backend:8000
+
+RUN npm run build
+
+# ==========================================
+# Stage 3: Production runner
+# ==========================================
+FROM node:20-alpine AS runner
+WORKDIR /app
+
+ENV NODE_ENV=production
+ENV NEXT_TELEMETRY_DISABLED=1
+
+RUN addgroup --system --gid 1001 nodejs
+RUN adduser --system --uid 1001 nextjs
+
+COPY --from=builder /app/public ./public
+
+# Standalone output
+COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
+COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
+
+USER nextjs
+
+EXPOSE 3000
+ENV PORT=3000
+ENV HOSTNAME="0.0.0.0"
+
+CMD ["node", "server.js"]