feat: add credentials validation for knowledge server

Author: mdesmet

src/datapilot/core/knowledge/cli.py

@@ -4,6 +4,7 @@
 
 from datapilot.cli.decorators import auth_options
 
+from ...clients.altimate.utils import validate_credentials
 from .server import KnowledgeBaseHandler
 
 
@@ -23,6 +24,10 @@ def serve(token, instance_name, backend_url, port):
         )
         raise click.Abort
 
+    if not validate_credentials(token, backend_url, instance_name):
+        click.echo("Error: Invalid credentials.")
+        raise click.Abort
+
     # Set context data for the handler
     KnowledgeBaseHandler.token = token
     KnowledgeBaseHandler.instance_name = instance_name