feat: add ndarray/base/scalar-dtype (issue #11002)

[Suhaniahirwar20]

Resolves #11002.

Description

What is the purpose of this pull request?

This pull request introduces a new utility @stdlib/ndarray/base/scalar-dtype to resolve a default ndarray data type from a scalar value.

Previously, scalar-to-dtype resolution logic was duplicated across multiple packages such as:

• ndarray/base/atleastnd
• ndarray/from-scalar

This PR extracts that logic into a reusable module, improving maintainability, consistency, and making it easier to extend support for additional data types in the future.

Changes include:

• Adding new package @stdlib/ndarray/base/scalar-dtype
• Refactoring ndarray/base/atleastnd to use the new utility
• Removing duplicated scalar dtype resolution logic

Related Issues

Does this pull request have any related issues?

This pull request has the following related issues:

• [RFC]: add ndarray/base/scalar-dtype #11002

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request?

No.

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

If you answered "yes" above, how did you use AI assistance?

• Code generation (e.g., when writing an implementation or fixing a bug)
• Test/benchmark generation
• Documentation (including examples)
• Research and understanding

Disclosure

I consulted ChatGPT to better understand the existing codebase and refactoring approach. The implementation and final changes were written and verified manually.

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@stdlib-js/reviewers

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