link Coverage Pass

Summary

Do one narrow non-React pass on @platejs/link.

Focus on the remaining real seams:

• BaseLinkPlugin
• withLink.normalizeNode
• wrapLink
• unwrapLink
• upsertLinkText

Do not broaden this into a /react pass or another upsertLink rewrite.

Constraints

• fast lane only
• no /react
• no wrapper vanity coverage
• fix a runtime bug only if the new direct tests expose one

Planned Coverage

1. BaseLinkPlugin.spec.tsx

   • valid html link parse
   • invalid or missing href rejected

2. withLink.spec.tsx

   • normalizeNode inserts a trailing text leaf after a terminal link

3. wrapLink.spec.tsx

   • wraps expanded text with a link element and preserves surrounding text

4. unwrapLink.spec.tsx

   • unwraps a whole link
   • split mode only unwraps the selected fragment inside a link

5. upsertLinkText.spec.tsx

   • replaces children when text changes
   • preserves marks from the first text child
   • no-op when text is unchanged or missing

Verification

• targeted bun test on touched link specs
• bun test packages/link/src
• pnpm test:profile -- --top 20 packages/link/src
• pnpm test:slowest -- --top 20 packages/link/src
• pnpm install
• pnpm turbo build --filter=./packages/link
• pnpm turbo typecheck --filter=./packages/link
• pnpm lint:fix

Deferred

• /react components and floating-link helpers
• utility files that already have direct specs
• more withLink branches unless these direct tests expose real debt