Suggest using the baseline / disabling error codes

```
> mypy
100000000000000000000000 errors detected
Maybe you should consider `mypy --write-baseline` or adding `allow-any-expression = true` to your config file.
```

Start by tracing the diagnostic output that reports the error count and suggests configuration options. Determine how baseline generation and error-code disabling are represented, then add the requested suggestion and tests confirming it appears for large error reports.

Written by the indexing model from the issue text.