Fix Kubernetes namespaces for dotted usernames

kubernetes_service.py

@@ -3,6 +3,7 @@ from datetime import datetime
 from kubernetes import client, config
 from kubernetes.client.rest import ApiException
 from kubernetes.stream import stream
+from namespace_utils import is_valid_namespace_name
 import os
 import random
 from runtime_config import (
@@ -62,8 +63,9 @@ class KubernetesManager:
             return False
 
     def create_namespace(self, namespace_name: str, labels: Dict = None) -> bool:
-        # Kubernetes namespaces MUST be lowercase
-        namespace_name = namespace_name.lower()
+        if not is_valid_namespace_name(namespace_name):
+            logger.error("Refusing to create invalid Kubernetes namespace name: %r", namespace_name)
+            return False
 
         if not self.connected:
             logger.info(f"⚠ Kubernetes not connected, skipping namespace creation for {namespace_name}")