feat: scaffold v2 project structure with Docker, FastAPI, and config

동작하는 최소 코드 수준의 v2 스캐폴딩:

- docker-compose.yml: postgres, fastapi, kordoc, frontend, caddy
- app/: FastAPI 백엔드 (main, core, models, ai, prompts)
- services/kordoc/: Node.js 문서 파싱 마이크로서비스
- gpu-server/: AI Gateway + GPU docker-compose
- frontend/: SvelteKit 기본 구조
- migrations/: PostgreSQL 초기 스키마 (documents, tasks, processing_queue)
- tests/: pytest conftest 기본 설정
- config.yaml, Caddyfile, credentials.env.example 갱신

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/Dockerfile

@@ -0,0 +1,16 @@
+FROM node:20-slim AS build
+
+WORKDIR /app
+COPY package.json .
+RUN npm install
+COPY . .
+RUN npm run build
+
+FROM node:20-slim
+WORKDIR /app
+COPY --from=build /app/build build/
+COPY --from=build /app/node_modules node_modules/
+COPY package.json .
+
+EXPOSE 3000
+CMD ["node", "build"]