test: add python fixtures support for stats/incr/wmean

[Om-A-osc]

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type: pre_commit_static_analysis_report
description: Results of running static analysis checks when committing changes.
report:

• task: lint_filenames
  status: passed
• task: lint_editorconfig
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• task: lint_typescript_tests
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Description

What is the purpose of this pull request?

This pull request:

• Adds Python-based test fixtures for @stdlib/stats/incr/wmean.
• Uses NumPy to generate batch-computed weighted means for prefix sequences.
• Produces double-precision (float64) data.json fixtures for validating the optimized single-pass incremental weighted mean implementation.
• Improves test coverage and numerical correctness guarantees for the package.

Related Issues

Does this pull request have any related issues?

No related issues.

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

• Test fixtures are generated using Python + NumPy, ensuring IEEE-754 double-precision reference values.
• The fixtures are intended solely for testing and do not affect runtime behavior.
• Contributing guidelines were read and followed.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

AI Assistance

When authoring the changes proposed in this PR, did you use any kind of AI assistance?

• Yes
• No

Disclosure

No AI assistance was used in the implementation, tests, or documentation.

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@stdlib-js/reviewers

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/incr/wmean	$\color{green}174/174$ $\color{green}+100.00%$	$\color{green}7/7$ $\color{green}+100.00%$	$\color{green}2/2$ $\color{green}+100.00%$	$\color{green}174/174$ $\color{green}+100.00%$

The above coverage report was generated for the changes in this PR.