feat: add C implementation blas/ext/base/ndarray/ssumpw

[Arjan-P]

Resolves part of #14404.

Description

What is the purpose of this pull request?

This pull request:

• Add C implementation for blas/ext/base/ndarray/ssumpw

Related Issues

Does this pull request have any related issues?

This pull request has the following related issues:

• [RFC]: add ndarray interface variants for missing modules in @stdlib/blas/ext/base #14404

Questions

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No.

Other

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No.

Checklist

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• Read, understood, and followed the contributing guidelines.

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[Planeshifter]

⚠️ Issue Reference Review

An automated check found potentially unrelated issue/PR references in this PR:

Reference	Assessment	Reasoning
#14404	suspicious	Issue #14404 tracks creating ndarray interface variants for @stdlib/blas/ext/base modules that currently lack one. ssumpw does not appear anywhere in that issue's checklist (only sdssum/sdssumpw are listed under the s prefix), and this PR's diff shows @stdlib/blas/ext/base/ndarray/ssumpw already existed as a package (only lib/index.js and package.json are modified; the rest are new C/native-addon files) — i.e. it adds a native C implementation to an already-existing ndarray package rather than creating a missing ndarray interface.

Why this matters: GitHub automatically closes issues referenced with
closing keywords (Resolves, Closes, Fixes) when the PR is merged. Incorrect
references can accidentally close unrelated issues.

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• If the reference is incorrect, please update your PR description.

This assessment was generated by an AI model and is informational only.

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