updated README

[vighnesh-xi]

Summary

Improved the PocketFlow RAG tutorial to make the offline and online stages clearer, and made the run instructions easier to follow.

What changed

• Clarified the difference between the offline indexing stage and the online question-answering stage.
• Added simpler explanations for each node in the flow.
• Improved the notes around how PocketFlow separates document preparation from question answering.
• Cleaned up the run instructions and the example explanation.

Why

The previous README was a bit hard to follow for first-time users. This version makes the tutorial easier to understand, especially for readers trying to learn how PocketFlow structures a RAG pipeline.

Testing

• Reviewed the tutorial text for clarity and flow.
• Verified the updated explanation matches the PocketFlow RAG design pattern.

Notes

• This is a documentation-only change.