feat: add new Hudi demo app hudi-notebooks

[deepakpanda93]

Describe the issue this Pull Request addresses

This PR adds initial support for running Apache Hudi with PySpark inside Jupyter notebooks. While Hudi already supports PySpark, notebook environments like Jupyter require additional handling for:

• Spark session setup with Hudi-specific JARs
• Common pitfalls when using Hudi SQL procedures from spark.sql() in Python notebooks

This improvement aims to make it easier for developers to experiment with Hudi inside Jupyter notebooks

Summary and Changelog

• Adds utility functions for initializing Hudi within Jupyter notebooks
• Clarifies the usage of Hudi's SQL procedures inside notebook cells

Impact

This change improves the developer experience for PySpark and Jupyter users who work with Apache Hudi. There is no change to core APIs or storage format, and no impact on runtime behavior.

Risk Level

none

Documentation Update

• Yes. It is in plan to add Jupyter-compatible examples and usage notes
• Will submit follow-up PR to asf-site under the "Getting Started" or "How-To Guides" section

Contributor's checklist

• Read through contributor's guide
• Enough context is provided in the sections above
• Adequate tests were added if applicable

[hudi-bot]

CI report:

• 215a52d Azure: SUCCESS

Bot commands

@hudi-bot supports the following commands:

• @hudi-bot run azure re-run the last Azure build

[xushiyan]

lgtm on a skim. this PR is self-contained within hudi-notebooks/ not affecting other code paths. expect more future iterations on the content

[xushiyan]

@deepakpanda93 please research on how to add tests for notebooks so the content can be verified by CI. this can be done in next PR specifically for adding tests to CI. it can be a separate job in CI just to test notebooks