fix: use set_token() instead of token= constructor arg

MonarchMoney constructor no longer accepts token= kwarg, use set_token() instead

src/monarch_mcp_custom/auth.py

@@ -55,7 +55,8 @@ async def get_authenticated_client() -> MonarchMoney:
     token = load_token()
     if token:
         try:
-            _client_instance = MonarchMoney(token=token)
+            _client_instance = MonarchMoney()
+            _client_instance.set_token(token)
             return _client_instance
         except Exception as e:
             logger.error(f"Failed to initialize MonarchMoney with token: {e}")