feat: add Valibot support for structured outputs

[Oxygen56]

Adds valibotResponseFormat() for using Valibot schemas with structured outputs.

Summary

This PR adds first-class Valibot support for structured outputs, following the same pattern as the existing Zod integration.

Changes

• Added src/helpers/valibot.ts with valibotResponseFormat(), valibotTextFormat(), valibotFunction(), and valibotResponsesFunction() helpers
• Added tests/helpers/valibot.test.ts with comprehensive test coverage
• Added valibot and @valibot/to-json-schema as optional peer dependencies

How it works

The implementation converts Valibot schemas to JSON Schema using @valibot/to-json-schema (targeting draft-07), then applies the same strict mode transformation used by the Zod helpers. The v.parse() function is used for response parsing.

Usage

const completion = await client.chat.completions.parse({
  model: 'gpt-4o-2024-08-06',
  messages: [{ role: 'user', content: 'What is the weather like?' }],
  response_format: valibotResponseFormat(
    v.object({
      city: v.string(),
      temperature: v.number(),
      units: v.picklist(['c', 'f']),
    }),
    'location',
  ),
});

Closes #1021

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Restore the registry host in the lockfile

This commit rewrites nearly every existing resolved entry from registry.yarnpkg.com to registry.npmmirror.com (Yarn's lockfile records resolved as the tarball URL: https://classic.yarnpkg.com/en/docs/yarn-lock). In CI or user environments that cannot reach that mirror or expect dependencies from the canonical registry, yarn install --frozen-lockfile will now fetch from the mirror and can fail or bypass the expected registry; only the new Valibot-related entries should have been added.

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