Added Usage Example section to README (Fixes #13714)

[yeshuawm999]

Describe your change:

Added a new “Usage Example” section to the README.md file.
This section explains how users can clone the repository, run algorithms locally, use the Python interactive shell, and run doctests.
It improves the documentation for beginners and new contributors.

Fixes #13714

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Type of change:

• Documentation change

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Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only modifies the README.md file.
• The Markdown style matches the existing format (emoji headers, indentation, and code blocks).
• The new section helps users understand how to clone, run, and test algorithms from the repository.
• The section includes properly formatted fenced code blocks for commands.
• This PR improves project usability for new contributors.