vegiveera/data-engineering_ ? reverse-engineered prompt

Build me a Databricks learning repo that demonstrates the main data engineering patterns in a hands on way.

I want a set of self contained notebooks and clear docs that walk through medallion architecture, Delta Lake, Auto Loader, streaming, Unity Catalog governance, SQL, MLflow, feature engineering, jobs orchestration, dashboards, Delta Sharing, and a simple GenAI RAG example. Please make it easy to follow, with each module showing a real end to end flow from raw data into Bronze, then cleaned Silver data, then curated Gold outputs.

This is for learning, not production, so keep the examples practical and explanatory. Include conceptual notes in the docs, runnable sample code in the notebooks, and simple setup instructions for Databricks Free Edition if possible. If you need to check current Databricks docs or APIs, look them up online.