feat: add client information logging to MCP connection rejection

Add reusable utility for extracting client information from ASGI scope:
- Create gns3server/utils/request_utils.py with extract_client_info()
- Extract client IP, port, path, method, and authenticated username
- Format comprehensive log messages with client context

Benefits:
- Better observability for connection rejection events
- Reusable utility for other modules
- Consistent client logging format across codebase
- Helps diagnose timing issues during server startup

Usage:
  from gns3server.utils.request_utils import extract_client_info
  client_info = extract_client_info(scope, auth_service)
  log.warning(f"Connection rejected - Client: {client_info['host']}:{client_info['port']} ({client_info['user_info']})")

gns3server/api/routes/mcp/__init__.py

@@ -44,6 +44,7 @@ from mcp.server.transport_security import TransportSecuritySettings
 
 from gns3server.config import Config
 from gns3server.services import auth_service
+from gns3server.utils.request_utils import extract_client_info
 from .projects import (
     list_projects_handler, get_project_handler, create_project_handler,
     delete_project_handler, open_project_handler, close_project_handler,
@@ -516,6 +517,11 @@ def _make_auth_wrapper(inner_app):
         server_ready = await wait_for_mcp_ready()
         if not server_ready:
             # Server initialization timed out - return 503 Service Unavailable
+            client_info = extract_client_info(scope, auth_service)
+            log.warning(
+                f"Rejecting MCP connection - GNS3 server initialization not complete. "
+                f"Client: {client_info['host']}:{client_info['port']} ({client_info['user_info']}, Path: {client_info['path']})"
+            )
             response = Response(
                 "GNS3 server initialization not complete - please retry later",
                 status_code=503

gns3server/utils/request_utils.py

@@ -0,0 +1,91 @@
+"""
+Utilities for extracting request information from ASGI scope.
+
+This module provides reusable functions for extracting client information
+from ASGI scope dictionaries for logging and debugging purposes.
+"""
+
+import logging
+from urllib.parse import parse_qs
+from typing import Dict, Any, Optional
+
+log = logging.getLogger(__name__)
+
+
+def extract_client_info(scope: Dict[str, Any], auth_service_instance: Optional[Any] = None) -> Dict[str, str]:
+    """
+    Extract client information from ASGI scope for logging purposes.
+
+    Args:
+        scope: ASGI scope dictionary containing request metadata
+        auth_service_instance: Optional auth service instance for token validation
+
+    Returns:
+        Dictionary with client information:
+        - host: Client IP address
+        - port: Client port
+        - path: Request path
+        - method: Request method
+        - username: Authenticated username (if token provided and valid)
+        - user_info: Human-readable user info string
+    """
+    # Extract client address and port
+    client = scope.get("client", (None, None))
+    client_host = client[0] if client and client[0] else "unknown"
+    client_port = str(client[1]) if client and len(client) > 1 else "unknown"
+
+    # Extract request info
+    path = scope.get("path", "unknown")
+    method = scope.get("method", "unknown")
+
+    # Try to extract username from token
+    username = None
+    if auth_service_instance:
+        try:
+            headers = dict(scope.get("headers", []))
+            auth = headers.get(b"authorization", b"").decode()
+            token = None
+
+            # Try Authorization header
+            if auth.startswith("Bearer "):
+                token = auth[7:]
+
+            # Try query parameter
+            if not token:
+                params = parse_qs(scope.get("query_string", b"").decode())
+                tokens = params.get("token", [])
+                if tokens:
+                    token = tokens[0]
+
+            # Validate and extract username
+            if token:
+                username = auth_service_instance.get_username_from_token(token)
+        except Exception as e:
+            log.debug(f"Failed to extract username from token: {e}")
+            username = None
+
+    # Create user-friendly info string
+    user_info = f"user '{username}'" if username else "unauthenticated user"
+
+    return {
+        "host": client_host,
+        "port": client_port,
+        "path": path,
+        "method": method,
+        "username": username,
+        "user_info": user_info
+    }
+
+
+def format_client_log(client_info: Dict[str, str], message: str) -> str:
+    """
+    Format a log message with client information.
+
+    Args:
+        client_info: Client information dict from extract_client_info()
+        message: Log message
+
+    Returns:
+        Formatted log string with client prefix
+    """
+    return f"{message} - Client: {client_info['host']}:{client_info['port']} ({client_info['user_info']}, Path: {client_info['path']})"