Pydantic AI Harness tool-call limit bypass in nested CodeMode calls

Pydantic AI Harness before 0.59.0 fails to enforce UsageLimits.toolcallslimit on nested tool calls dispatched from runcode in the CodeMode toolset. Users or prompt-injected content can make the sandboxed program invoke tools via runnestedcall without checkbeforetoolcall, exceeding operator limits...