fix(learn): split pip and imports so CI can run 00-fine-tuning.ipynb

The run-notebook converter puts cells containing !pip entirely in run.sh
and excludes them from the Python script. The first cell mixed pip install
with imports and chains.py download, so the script never got the imports.
Split into two cells: pip only, then imports and chains download.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: jhamon