Adds unsaved-warning hidden by default, oninput dirty marker, form error banner hidden when form is undefined. 3 new tests covering ~6 branches. Refs #496. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Adds unsaved-warning hidden by default, oninput dirty marker, form error banner hidden when form is undefined. 3 new tests covering ~6 branches. Refs #496. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>