feat: support parallel builds

[Sunny-117]

No description provided.

[pi0]

Thanks for PR. However it might be beneficial, it causes a behavior change and can potentially breaks projects (for example if result of first mkdist is needed for second rollup, for types, etc)

Can you please move it behind a flag like parallel: true? 🙏🏼

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[Sunny-117]

Thanks for PR. However it might be beneficial, it causes a behavior change and can potentially breaks projects (for example if result of first mkdist is needed for second rollup, for types, etc)

Can you please move it behind a flag like parallel: true? 🙏🏼

Thank you so much for your suggestion! Based on your advice, I’ve added a flag: parallel, which defaults to false and is provided as an experimental feature. 🙏🏼

[pi0]

This is almost correct however we need to do something like ()=>copybuild(ctx) here because otherwise regardless of awaiting or not, they will be started immediately in parallel

[Sunny-117]

Oh, I was careless—it's already fixed now.