feat: add C implementation for stats/base/ndarray/smeanpw

[AtharvaPatange]

Resolves none

Description

What is the purpose of this pull request?

This pull request:

• feat: add C implementation for stats/base/ndarray/smeanpw

Related Issues

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This pull request has the following related issues:

• none

Questions

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No.

Other

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No.

Checklist

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

• Read, understood, and followed the contributing guidelines.

AI Assistance

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• No

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• Code generation (e.g., when writing an implementation or fixing a bug)
• Test/benchmark generation
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Disclosure

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{{TODO: add disclosure if applicable}}

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@stdlib-js/reviewers

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[LoayAhmed304]

Copyright year for newly created files should be 2026. Same should apply to src/Makefile, test/test.main.js, and test/test.native.js. However it should be kept to 2025 in README.md