feat(gns3-copilot): add get_gns3_server_host utility and integrate into Nornir tools

- Add `get_gns3_server_host()` function to `connector_factory.py` for extracting GNS3 server hostname from controller, config, or default URL
- Export new function in `__init__.py` for public API access
- Replace `os.getenv("GNS3_SERVER_HOST", "127.0.0.1")` calls with `get_gns3_server_host()` in Nornir configuration tools (`config_tools_nornir.py`, `display_tools_nornir.py`)
- Ensures consistent host detection across tools using the same priority logic as `get_gns3_connector`

gns3server/agent/gns3_copilot/gns3_client/__init__.py

@@ -27,7 +27,11 @@ Main functions:
 - get_gns3_connector_with_llm_config: Factory function to create connector AND retrieve LLM config
 """
 
-from .connector_factory import get_gns3_connector, get_gns3_connector_with_llm_config
+from .connector_factory import (
+    get_gns3_connector,
+    get_gns3_connector_with_llm_config,
+    get_gns3_server_host,
+)
 from .custom_gns3fy import (
     CONSOLE_TYPES,
     LINK_TYPES,
@@ -93,6 +97,7 @@ __all__ = [
     "GNS3UpdateDrawingTool",
     "get_gns3_connector",
     "get_gns3_connector_with_llm_config",
+    "get_gns3_server_host",
     "add_file_to_index",
     "get_file_list",
 ]

gns3server/agent/gns3_copilot/gns3_client/connector_factory.py

@@ -298,3 +298,40 @@ def _detect_url_for_api() -> Optional[str]:
 
     # Fallback
     return DEFAULT_GNS3_URL
+
+
+def get_gns3_server_host() -> str:
+    """
+    Get GNS3 server hostname from Controller or Config.
+
+    This is a convenience function for extracting the hostname only,
+    useful for Nornir tools that need the GNS3 server address.
+
+    Uses the same priority order as get_gns3_connector:
+    1. Controller.instance().compute("local")
+    2. Config.instance().settings.Server
+    3. Fallback to DEFAULT_GNS3_URL host
+
+    Returns:
+        Hostname/IP address string
+
+    Example:
+        from gns3_copilot.gns3_client import get_gns3_server_host
+
+        host = get_gns3_server_host()
+        print(f"GNS3 server host: {host}")
+    """
+    url = _detect_url_for_api()
+
+    # Extract host from URL
+    # URL format: protocol://host:port
+    try:
+        # Remove protocol prefix
+        host_part = url.split("://")[1]
+        # Extract host (before the port)
+        host = host_part.split(":")[0]
+        logger.debug("Extracted GNS3 server host: %s from URL: %s", host, url)
+        return host
+    except Exception as e:
+        logger.warning("Failed to extract host from URL %s: %s, using fallback", url, e)
+        return DEFAULT_GNS3_URL.split("://")[1].split(":")[0]