feat: add napi/create-int64 and napi/create-uint64

[Kaushikgtm]

Resolves a part of #10922

Resolves #{{TODO: add issue number}}.

Description

What is the purpose of this pull request?

Adds @stdlib/napi/create-int64 and @stdlib/napi/create-uint64, wrapping
napi_create_bigint_int64 and napi_create_bigint_uint64 (N-API v6+). These
unblock the TODOs in blas/base/icamax, blas/base/idamax, etc., which need to
return 64-bit integers.

• {{TODO: add description describing what this pull request does}}

Related Issues

Does this pull request have any related issues?

This pull request has the following related issues:

• #{{TODO: add related issue number}}

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

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

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• 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
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Disclosure

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{{TODO: add disclosure if applicable}}

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