feat: add copyWithIn method to array/uint64

[DivitJain26]

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

Description

What is the purpose of this pull request?

This pull request:

• Adds copyWithIn method to Uint64Array.

Related Issues

Does this pull request have any related issues?

This pull request has the following related issues:

• #{{TODO: add related issue number}}

Questions

Any questions for reviewers of this pull request?

No.

Other

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.

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

If you answered "yes" to using AI assistance, please provide a short disclosure indicating how you used AI assistance. This helps reviewers determine how much scrutiny to apply when reviewing your contribution. Example disclosures: "This PR was written primarily by Claude Code." or "I consulted ChatGPT to understand the codebase, but the proposed changes were fully authored manually by myself.".

{{TODO: add disclosure if applicable}}

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@stdlib-js/reviewers

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
array/uint64	$\\color{red}1350/1355$ $\\color{green}+0.01\\%$	$\\color{red}202/206$ $\\color{green}+0.01\\%$	$\\color{green}22/22$ $\\color{green}+0.00\\%$	$\\color{red}1350/1355$ $\\color{green}+0.01\\%$

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

[DivitJain26]

Self Note:

• Use reinterpret in tests and benchmarks.