feat: implement MC domain filter proxy, API, dashboard

- proxy: asyncio TCP proxy with handshake parser, domain whitelist,
  transparent backend tunneling, SQLite logging, mtime hot reload
- api: FastAPI routes for config/domains/logs/status + restart trigger
- frontend: React + Vite NPM-style dashboard (dashboard/domains/logs/settings)
- nginx: reverse proxy for /api -> api:8000 and / -> frontend:3000
- docker-compose: full stack with shared data volume
- replace spec mc-domain-filter.md with README.md

frontend/Dockerfile

@@ -0,0 +1,17 @@
+# 빌드 단계
+FROM node:20-alpine AS build
+WORKDIR /app
+COPY package.json ./
+RUN npm install --no-audit --no-fund
+COPY . ./
+RUN npm run build
+
+# 서빙 단계: vite preview 로 dist/ 정적 서빙
+FROM node:20-alpine
+WORKDIR /app
+COPY --from=build /app/package.json ./
+COPY --from=build /app/node_modules ./node_modules
+COPY --from=build /app/dist ./dist
+COPY --from=build /app/vite.config.js ./
+EXPOSE 3000
+CMD ["npx", "vite", "preview", "--host", "0.0.0.0", "--port", "3000"]