chore: apply pending code updates

src/server/services/config_service.py

@@ -8,6 +8,7 @@ This service handles:
 """
 
 import json
+import logging
 import shutil
 from datetime import datetime
 from pathlib import Path
@@ -15,6 +16,8 @@ from typing import Dict, List, Optional
 
 from src.server.models.config import AppConfig, ConfigUpdate, ValidationResult
 
+logger = logging.getLogger(__name__)
+
 
 class ConfigServiceError(Exception):
     """Base exception for configuration service errors."""
@@ -136,7 +139,7 @@ class ConfigService:
                 self.create_backup()
             except ConfigBackupError as e:
                 # Log but don't fail save operation
-                print(f"Warning: Failed to create backup: {e}")
+                logger.warning("Failed to create backup: %s", e)
         
         # Save configuration with version
         data = config.model_dump()