perf: avoid loading parser in client and cache define

[KermanX]

Try to improve performance via multiple small improvements.

I have no idea why some of the smoke tests fail 🫠

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@slidev/client

pnpm add https://pkg.pr.new/slidevjs/slidev/@slidev/client@1812

create-slidev

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@slidev/parser

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@slidev/cli

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@slidev/types

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commit: 8dba364