Upgrade Python tooling and refresh course samples

[BrianKolowitz]

Summary

• add Python 3.12 dependency manifests plus README guidance for installing runtime and developer tooling
• modernize the lecture helper scripts, sample tests, and data utilities to avoid deprecated APIs and improve compatibility
• add a GitHub Actions workflow to lint the curated Python sources with Ruff and run the pytest suite on Python 3.12

Testing

• ruff check _exclude 'lectures/Week 02 - Processing files, Making Web Requests' 'lectures/Week 04 - Data Processing and Visualization Part 1/Manifold_Approximation_and_Projection.py' 'lectures/Week 06 - Web Scraping/scrapers' 'lectures/Week 01 - Language basics, Generating Data, Storing Data/test_class.py' 'lectures/Week 01 - Language basics, Generating Data, Storing Data/test_sample.py' 'lectures/Week 01 - Language basics, Generating Data, Storing Data/test_tmpdir.py' 'lectures/Week 01 - Language basics, Generating Data, Storing Data/test_tmppath.py' 'lectures/Week 01 - Language basics, Generating Data, Storing Data/test_sysexit.py'
• pytest

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Codex Task