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

.gitignore

@@ -0,0 +1,23 @@
+# 런타임 데이터 (컨테이너가 생성)
+data/config.json
+data/logs.db
+data/logs.db-wal
+data/logs.db-shm
+
+# 노드/파이썬 빌드 산출물
+node_modules/
+dist/
+.vite/
+__pycache__/
+*.pyc
+*.pyo
+
+# 에디터/OS
+.vscode/
+.idea/
+.DS_Store
+*.swp
+
+# 환경변수
+.env
+.env.*