- Add list_node_files, get_node_file, write_node_file, delete_node_file methods to Gns3Connector
- Add MCP handlers with offset/limit line-based reading for get_node_file
- Auto-truncate files >50KB with truncated flag in response
- Rich metadata returned (total_lines, total_bytes, has_more, etc.)
- Tool docstrings guide AI to check file sizes before reading chunked