Slate React void keyboard navigation needs post-native sync and Shift model ownership

Problem

/examples/images exposed DOM/model drift around selectable block voids. Plain ArrowLeft/ArrowRight already moved through images correctly, but vertical native movement and Shift-extended horizontal movement split the browser selection from Slate selection.

Symptoms

ArrowDown from the end of the paragraph before an image put the DOM selection in the image spacer at [1,0]@0, while Slate stayed at [0,0]@113.
The image did not show the selected box shadow because useSelected() still read the stale model selection.
Shift+ArrowRight from [0,0]@113 let the DOM expand to the image wrapper, but Slate stayed collapsed. A second press moved Slate to the image while the DOM focus had already moved to the following wrapper.

What Didn't Work

Checking plain ArrowRight/ArrowLeft only. Those paths were already model-owned and green, so they missed the broken native and Shift paths.
Trusting the first selectionchange after ArrowDown. Chrome fired importable selectionchange work before the final native selection around the void spacer was stable.
Treating Shift+ArrowRight as browser-native. For void/read-only boundaries, letting the browser extend selection produces wrapper endpoints instead of canonical Slate text points.

Solution

Keep horizontal Shift movement model-owned:

if (Hotkeys.isExtendBackward(nativeEvent)) {
  return {
    axis: 'horizontal',
    extend: true,
    kind: 'move-selection',
    reverse: true,
  }
}
if (Hotkeys.isExtendForward(nativeEvent)) {
  return { axis: 'horizontal', extend: true, kind: 'move-selection' }
}

Then have the caret engine execute it through editor.move({ edge: 'focus' }) instead of native DOM extension:

if (Hotkeys.isExtendForward(nativeEvent)) {
  event.preventDefault()
  editor.update(() => {
    editor.move({ edge: 'focus', reverse: isRTL })
  })
  return caretMovementHandled()
}

For native vertical movement, keep the browser in charge of layout but import the settled DOM selection after the keydown default action:

if (
  !readOnly &&
  decision.intent === 'native-selection-move' &&
  (event.key === 'ArrowUp' || event.key === 'ArrowDown')
) {
  setTimeout(() => {
    syncEditorSelectionFromDOM({ editor, inputController })
  })
}

Guard the behavior in /examples/images with browser rows for:

ArrowRight into an image and out to the next paragraph.
ArrowDown into an image with model selection, DOM selection, and selected image styling all aligned.
Shift+ArrowRight from before an image with Slate focus and DOM focus both on the void text point.

Why This Works

Block-void images have a real zero-width text spacer, but the browser can land on wrapper-shaped DOM endpoints during native movement. Slate's model must only accept canonical text points. Horizontal Shift movement does not need browser layout, so model-owned editor.move({ edge: 'focus' }) is the right owner. Vertical movement does need native layout, so Slate must wait until the browser settles the selection, then import the final DOM point.

Prevention

When a keyboard bug mentions voids, test plain movement, vertical movement, and Shift-extended movement. One green path does not prove the family.
Browser rows for selectable voids should assert model selection, DOM selection, and visible selected state.
If native movement is allowed, prove the post-native import timing in a real browser. A selectionchange trace can be too early around zero-width void spacers.