Summary
Improve contributor clarity around the difference between combined-stages and use-cases directories in the examples repo.

Description
As a contributor reviewing the InstructLab/examples repo, the distinction between use-cases and combined-stages notebooks was not immediately clear.
To improve onboarding and submission clarity, the README could benefit from a more explicit explanation of these categories.

Acceptance Criteria
[] Review existing README and identify areas for improvement.
[] Draft clearer descriptions for each directory with example notebook types.
[] Open GitHub issue or PR to update the README.