feat(agent): update import paths for gns3_copilot modules

Updated import statements across multiple agent files to use absolute paths starting with `gns3server.agent.gns3_copilot` instead of relative `gns3_copilot` imports. This ensures proper module resolution within the gns3-server package structure and prevents import errors when the agent is executed from different contexts.

gns3server/agent/gns3_copilot/tools_v2/gns3_create_node.py

@@ -13,7 +13,7 @@ from typing import Any
 from langchain.tools import BaseTool
 from langchain_core.callbacks import CallbackManagerForToolRun
 
-from gns3_copilot.gns3_client import Node, get_gns3_connector
+from gns3server.agent.gns3_copilot.gns3_client import Node, get_gns3_connector
 
 # Configure logging
 logger = logging.getLogger(__name__)