fix(plugin-annotation): mark FreeText as editing on input so blur doesn't drop changes

[seanlim]

Closes #681

Root cause

In packages/plugin-annotation/src/shared/components/annotations/free-text.tsx (and callout-free-text.tsx), the commit-on-blur is gated by editingRef.current:

const handleBlur = () => {
  if (!editingRef.current) return;        // gate
  editingRef.current = false;
  ...
  annotationProvides.updateAnnotation(pageIndex, annotation.object.id, {
    contents: editorRef.current.innerText.replace(/\u00A0/g, ' '),
  });
};

editingRef.current is only ever armed inside the [isEditing] effect:

useEffect(() => {
  if (isEditing && editorRef.current) {
    editingRef.current = true;
    editor.focus();
    ...
  }
}, [isEditing]);   // runs only when isEditing CHANGES

When the style-panel interaction blurs the editor, handleBlur runs and sets editingRef.current = false. The annotation stays selected, so isEditing never changes and the effect doesn't re-run. Re-focusing the still-contentEditable span does not re-arm the gate (there is no onFocus handler), so the next blur bails out before committing.

Proposed fix

Re-arm the gate whenever the user actually edits the text, on the contentEditable element in both free-text.tsx and callout-free-text.tsx:

<span
  ref={editorRef}
  onBlur={handleBlur}
  onInput={() => {
    editingRef.current =
 true;
  }}
  tabIndex={0}
  ...
>

A single onInput handler is sufficient. A contentEditable only emits input when it's editable and its content actually changes, so "the user typed something" guarantees editingRef.current is armed before the next blur — which is the only case where text would otherwise be lost. (Verified against the repro above; re-arming on onFocus instead/additionally isn't needed, since a focus/blur with no typing has nothing new to commit.)

Testing

Ran the snippet viewer @embedpdf/snippet and added a FreeText annotation, typed text, blurred — text persists.

Re-edited the existing annotation, typed more, blurred — change is saved and the comment sidebar reflects the updated text (this is the path that previously dropped the edit).

[vercel]

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