fix(docs): improve TanStack Form example performance

[PhilemonChiro]

Summary

• Change validation strategy from onChange to onBlur in the ExampleForm component
• Prevents full Zod schema validation on every keystroke

Problem

The ExampleForm in the internal sink uses validators: { onChange: exampleFormSchema }, which validates the entire Zod schema on every keystroke. The schema contains expensive operations (regex checks, date calculations, refine() calls), causing noticeable input lag when typing in text fields.

Note: The GitHub issue mentions the "Bug Report Form", but that form (form-tanstack-demo.tsx) already uses onSubmit validation, which is correct. The actual performance issue is in example-form.tsx.

Solution

Changed validation to onBlur strategy:

• Validates when a field loses focus (user tabs/clicks away)
• User can type freely without lag
• Matches the pattern used in other TanStack Form examples (e.g., form-tanstack-array.tsx)

File Changed

• apps/v4/app/(internal)/sink/(pages)/tanstack-form/example-form.tsx (line 80)

Test plan

• Verified no TypeScript errors
• Type rapidly in the "Additional Comments" textarea - should have no lag

Fixes #9222

[vercel]

@PhilemonChiro is attempting to deploy a commit to the shadcn-pro Team on Vercel.

A member of the Team first needs to authorize it.