Footer only committed edited text via onBlur, and its effect rewrote
innerText from the (stale) text prop whenever selected became false --
if selection cleared without a real DOM blur, the in-progress edit was
silently lost. Adopt Heading.tsx's exact mechanism: an editedTextRef
updated on onInput, committed to the prop via an effect keyed on the
selected->false transition (in addition to the existing onBlur commit).
Preserves the 500ms setProp debounce Footer already had for undo grouping.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
