Implement reconnect, idle reporting, and security hardening

src/lazy_enter/__main__.py

@@ -1,10 +1,20 @@
 """CLI 엔트리포인트."""
 
+import sys
+
 from lazy_enter.bridge import Bridge
+from lazy_enter.config import Config
 
 
 def main() -> None:
-    bridge = Bridge()
+    config = Config()
+    try:
+        config.validate_required_settings()
+    except ValueError as exc:
+        print(f"[LazyEnter] 설정 오류: {exc}", file=sys.stderr)
+        raise SystemExit(1) from exc
+
+    bridge = Bridge(config)
     bridge.run()