fix(core): recover from hallucinated tool names instead of ending the scan

A tool call for a name Strix does not register raised ModelBehaviorError
from the SDK turn resolver, which nothing retries: the root agent's raise
tore down the whole scan and a sub-agent died before its status was set.
Opt into the SDK's tool_not_found_behavior="return_error_to_model" so the
unknown call comes back as a tool result and the agent self-corrects.

The setting landed in openai-agents 0.19.0, which requires openai>=2.45,
so both pins move.

.pre-commit-config.yaml

@@ -21,7 +21,7 @@ repos:
           fastapi,
           pytest,
           hatchling,
-          "openai-agents[litellm]==0.14.6",
+          "openai-agents[litellm]>=0.19.0,<0.20",
         ]
         args: [--install-types, --non-interactive]