Add typesVersions for legacy TypeScript moduleResolution support

[d-winter]

Summary

• Adds typesVersions field to package.json to support legacy TypeScript configurations
• Fixes subpath imports (/react, /core) for users with moduleResolution: "node"

Problem

Users with older TypeScript setups reported needing to change their tsconfig.json to moduleResolution: "bundler" to use this SDK. This broke other imports in their projects.

The root cause: TypeScript's moduleResolution: "node" doesn't read the exports field in package.json, so it couldn't resolve types for subpath imports like @hygraph/preview-sdk/react.

Solution

Added typesVersions as a fallback for legacy TypeScript resolution:

"typesVersions": {
  "*": {
    "react": ["./dist/react/index.d.ts"],
    "core": ["./dist/core/index.d.ts"]
  }
}

This is safe because TypeScript prioritizes exports over typesVersions when both are present - modern setups are unaffected.

Test Plan

• Verified legacy setup (moduleResolution: "node") fails without fix
• Verified legacy setup works with fix
• Verified modern setup (moduleResolution: "bundler") works before fix
• Verified modern setup still works after fix
• Verified SDK's own type-check passes