Apply suggestion from @Copilot

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: kevinbackhouse

src/seclab_taskflow_agent/mcp_servers/logbook/logbook.py

@@ -12,7 +12,6 @@
 from fastmcp import FastMCP # move to FastMCP 2.0
 import json
 from pathlib import Path
-import os
 from seclab_taskflow_agent.path_utils import mcp_data_dir
 
 mcp = FastMCP("Logbook")