fix(sorts): validate bucket count in bucket_sort

[jabrailkhalil]

Describe your change:

• 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.

bucket_sort() now raises a clear TypeError when bucket_count is not an integer, instead of failing later with an implementation-level error. The function signature also uses precise numeric list types, and a doctest documents the invalid-input behavior.

Fixes #14970

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".

Checks run:

• python -m doctest sorts\\bucket_sort.py
• python -m pytest sorts\\bucket_sort.py --doctest-modules
• python -m ruff check sorts\\bucket_sort.py
• python -m ruff format --check sorts\\bucket_sort.py
• python -m py_compile sorts\\bucket_sort.py