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

api/main.py

@@ -0,0 +1,33 @@
+"""MC Domain Filter 관리 API.
+
+FastAPI 로 설정/도메인/로그/상태 4개 라우터를 노출한다. 인증은 없으니
+공개 네트워크에 직접 노출하지 말 것 (nginx + basic auth 권장).
+"""
+from __future__ import annotations
+
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from routes import config as config_routes
+from routes import domains as domain_routes
+from routes import logs as log_routes
+from routes import status as status_routes
+
+app = FastAPI(title="MC Domain Filter API", version="0.1.0")
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+app.include_router(config_routes.router, prefix="/api", tags=["config"])
+app.include_router(domain_routes.router, prefix="/api", tags=["domains"])
+app.include_router(log_routes.router, prefix="/api", tags=["logs"])
+app.include_router(status_routes.router, prefix="/api", tags=["status"])
+
+
+@app.get("/health")
+def health() -> dict:
+    return {"ok": True}