docs: correct Foundry model deployment example to gpt-4o-mini

[satodayo]

Summary

• correct the Foundry model deployment example in the Episode 1 cookbook
• use gpt-4o-mini consistently with the rest of the notebook and environment variable examples

Testing

• not run (documentation-only change)

[farzad528]

Thanks @satodayo - this is a valid catch, and the inconsistency was still present (Episode 1 had gpt-4o in the env example while the rest of the notebook, the README, and the default deployment all use gpt-4o-mini).

Your branch predates the repo restructure under Foundry-IQ/, so it can no longer merge against the moved path. I have carried your exact change into #82 and credited you as a co-author. Closing this in favor of that PR - thank you for the contribution!