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/routes/status.py

@@ -0,0 +1,59 @@
+"""프록시 상태 및 통계."""
+from __future__ import annotations
+
+import sqlite3
+import time
+
+from fastapi import APIRouter
+
+from config_io import LOG_DB, load_config, save_config
+
+router = APIRouter()
+
+
+@router.get("/status")
+def status() -> dict:
+    cfg = load_config()
+    total = allowed = blocked = errored = 0
+    last_ts: float | None = None
+    if LOG_DB.exists():
+        con = sqlite3.connect(LOG_DB)
+        try:
+            total = con.execute("SELECT COUNT(*) FROM connections").fetchone()[0]
+            allowed = con.execute(
+                "SELECT COUNT(*) FROM connections WHERE action='allowed'"
+            ).fetchone()[0]
+            blocked = con.execute(
+                "SELECT COUNT(*) FROM connections WHERE action='blocked'"
+            ).fetchone()[0]
+            errored = con.execute(
+                "SELECT COUNT(*) FROM connections WHERE action='error'"
+            ).fetchone()[0]
+            row = con.execute(
+                "SELECT ts FROM connections ORDER BY id DESC LIMIT 1"
+            ).fetchone()
+            last_ts = row[0] if row else None
+        finally:
+            con.close()
+    return {
+        "proxy_enabled": cfg.get("proxy", {}).get("enabled", True),
+        "listen_port": cfg.get("proxy", {}).get("listen_port"),
+        "backend": cfg.get("backend"),
+        "domain_count": len(cfg.get("allowed_domains", [])),
+        "stats": {
+            "total": total,
+            "allowed": allowed,
+            "blocked": blocked,
+            "error": errored,
+            "last_event_ts": last_ts,
+        },
+        "server_time": time.time(),
+    }
+
+
+@router.post("/proxy/restart")
+def restart_proxy() -> dict:
+    """config 파일 mtime 을 갱신해서 프록시 watcher 가 재로드하게 한다."""
+    cfg = load_config()
+    save_config(cfg)
+    return {"ok": True, "note": "config touched; proxy will reload"}