fix(automation): address code review - path traversal fix and test marker

- Sanitise uploaded filenames with os.path.basename() to prevent path traversal
- Change TestWebhookDispatchIntegration marker from unit to integration

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

tests/test_automation.py

@@ -231,7 +231,7 @@ class TestDeliverAutomationHookTask:
 # ---------------------------------------------------------------------------
 
 
-@pytest.mark.unit
+@pytest.mark.integration
 class TestWebhookDispatchIntegration:
     """Test that dispatch_webhook_event also triggers automation hooks."""