fix: use unique confirm password input id

[mittalsonal]

Summary

• give the SignUpCardExample confirm-password input its own confirm-password id
• update the matching label htmlFor so clicking "Confirm Password" focuses the correct field
• keep the rendered example, displayed code block, and copy-button snippet in sync

Validation

• npx.cmd tsc --noEmit --pretty false
• git diff --check
• npm.cmd run build (passes; existing project-wide warnings remain unrelated to this focused fix)

Closes #699

[vercel]

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[mittalsonal]

Closing this as a duplicate of the existing PR #723 for the same assigned issue #699. Keeping #723 as the active review/merge target to avoid splitting maintainer attention.