[ShoaibAbbasDev]

Describe your change

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
• Documentation change?

Adds strings/lyndon_factorization.py, which implements Duval's algorithm for
the Lyndon factorization of a string. Every string can be written uniquely as a
non-increasing concatenation of Lyndon words, and the algorithm finds that
factorization in O(n) time with O(1) extra space.

• No existing Lyndon or Duval implementation in the repo.
• One function, lyndon_factorization(input_str: str) -> list[str], with type hints.
• Doctests cover repeated words, descending input, a single character, the
  empty string and a non-string input (TypeError).
• References: https://en.wikipedia.org/wiki/Lyndon_word and
  https://cp-algorithms.com/string/lyndon_factorization.html

Local checks: doctests, ruff check, ruff format, codespell and the
pre-commit hooks all pass.

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 changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues, then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".