Fix DocumentNode compatibility with exact optional properties

[JoviDeCroock]

Summary

• Allow explicit undefined on the optional DocumentNode.tokenCount property
• Preserve assignability with graphql's DocumentNode when exactOptionalPropertyTypes is enabled

Context

graphql@>=16.10 declares tokenCount as tokenCount?: number | undefined. Our narrower tokenCount?: number override rejects graphql.DocumentNode and packages extending it, such as @graphql-typed-document-node/core, when exact optional property types are enabled.

This causes the regression reported in urql-graphql/urql#3897 after @urql/core started consuming this package's DocumentNode type directly.

Test plan

• pnpm check
• pnpm lint
• pnpm exec vitest run
• pnpm build
• Verified the original @graphql-typed-document-node/core assignability reproduction compiles with the widened declaration

[changeset-bot]

🦋 Changeset detected

Latest commit: 906818c

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@0no-co/graphql.web	Patch

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