fix: add AITool to __all__ in __init__.py

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: jsonbailey

packages/sdk/server-ai/src/ldai/__init__.py

@@ -65,6 +65,7 @@
     'Judge',
     'JudgeConfiguration',
     'JudgeResult',
+    'AITool',
     'LDMessage',
     'ModelConfig',
     'ProviderConfig',