perf(install): switch over to modern-tar

[ayuhito]

If there is any appetite to reduce the dependency count, I'd love to suggest using modern-tar that solely relies on native APIs to reduce the surface area by 6 dependencies (additional 2MB unpacked). This brings the total package size down from 6MB to ~4MB when running npx for the first time.

This has a very small surface area which makes me believe this is a safe migration to undertake. Please let me know if there any concerns!

Ref: https://npmgraph.js.org/?q=node-jq

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On a side note, zod is around 3MB (almost 4MB if upgraded to zod@4). If we were to switch it out with something more native or even Zod Mini, the install size would significantly drop which would be a much faster initial npx experience. That would also be a very interesting avenue to explore.