feat: add Yup replacements

[yslpn]

🔗 Linked issue

Resolves #822

📚 Description

Adds yup to the preferred replacements manifest with two modular, tree-shakable alternatives:

• valibot
• zod/mini, provided by zod@^4.0.0

The shared schema-validation guide is designed for reuse by future schema-library mappings. It documents required fields, empty strings, validation pipelines/checks, async validation, type coercion, unknown object keys, and Zod Mini error locales. Both alternatives support Standard Schema.

The guide links to Zod Mini documentation and Schema Benchmarks without embedding version-sensitive benchmark figures.

⚠️ Disclosure

I am a maintainer of Valibot.

✅ Validation

• pnpm lint
• node scripts/validate-pr.ts

[43081j]

i would actually name this file something like schema-validation.md i think, and update the description:

Suggested change

	description: Modern alternatives to the yup package for TypeScript schema validation
	description: Modern alternatives for TypeScript schema validation

@gameroman what do you think? my reasoning is that we'll inevitably add more schema libraries over time. so this is a similar situation to fetch probably

[gameroman]

Maybe, in that case the whole doc should be changed probably to not be yup-specific?

[yslpn]

@gameroman @43081j I think it's a good idea to make it general.

If we reach an agreement, I'm ready to rewrite the entire document, making it less specific.