Fix: make notebook commands cross-platform and minimize unnecessary changes

[shardulmahamulkar]

This PR updates the notebook to improve cross-platform compatibility while keeping the changes minimal and focused.

Changes

• Replaced Linux-specific mkdir -p commands with os.makedirs() for cross-platform support
• Adjusted !gdown command usage to avoid issues on Windows
• Updated only the relevant notebook cell as requested

Notes

• Avoided modifying outputs or unrelated notebook metadata to keep the diff minimal and review-friendly
• This PR updates the previous submission based on review feedback to keep the diff minimal and focused.

Closes #463