feat: add stats/incr/nanmvmr

[coehemang]

Resolves #5615 .

Description

What is the purpose of this pull request?

This pull request:

• Adds the @stdlib/stats/incr/nanmvmr package, which computes moving variance-to-mean ratio (VMR) incrementally while handling NaN values by ignoring them.

Related Issues

Does this pull request have any related issues?

This pull request:

• resolves [RFC]: add stats/incr/nanmvmr #5615

Questions

Any questions for reviewers of this pull request?

No.

Other

Modified test cases are passing

Examples with NaN generated successfully

All 9 benchmarks are passed

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

No.

Checklist

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

• Read, understood, and followed the contributing guidelines.

---

@stdlib-js/reviewers

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Coverage Report

Package	Statements	Branches	Functions	Lines
stats/incr/nanmvmr	$\color{green}233/233$ $\color{green}+100.00\%$	$\color{green}11/11$ $\color{green}+100.00\%$	$\color{green}2/2$ $\color{green}+100.00\%$	$\color{green}233/233$ $\color{green}+100.00\%$

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

[Planeshifter]

/stdlib update-copyright-years