lighteval eval crashes on fresh install: GenerateConfig rejects frequence_penalty / log_probs / response_format with current inspect-ai #1327

Summary. A fresh pip install lighteval today resolves inspect-ai to the latest release (the dependency is declared as inspect-ai>=0.3.140 with no upper bound), and lighteval eval then fails at startup for any model/task with a pydantic ValidationError: current inspect_ai.model.GenerateConfig rejects unknown fields.

Repro:

pip install lighteval          # resolves inspect-ai 0.3.255 today
lighteval eval mockllm/model "lighteval|gsm8k|0" --max-samples 4 --log-dir out

ValidationError: 1 validation error for GenerateConfig
  Value error, Unknown GenerateConfig field(s): frequence_penalty, log_probs, response_format.

Root cause (lighteval/main_inspect.py): the config is built with three field names current inspect-ai doesn't accept — frequence_penalty (lines 270/477 — note this one is a typo; inspect-ai spells it frequency_penalty), log_probs (line 483; inspect-ai: logprobs), and response_format (line 489; no longer a GenerateConfig field).

Verified workaround until a fix lands: pip install "inspect-ai==0.3.140" — with that pin the same command runs to completion and writes results.

Suggested fix: rename the two fields, route response_format through extra_body or drop it, and consider an upper bound on inspect-ai so releases can't break installs retroactively. Happy to open a small PR for the renames if useful.

Environment: Python 3.12.13, lighteval 0.13.0, inspect-ai 0.3.255 (broken) / 0.3.140 (works), macOS.