Footnote Create Definition Repair

Goal

Add a definition-only repair path for unresolved footnote references so users can recreate a missing definition without inserting another reference.

Scope

• package-level createDefinition transform in @platejs/footnote
• unresolved footnote reference repair UI in the docs app
• focused tests, docs, and release notes for the new surface

Non-Goals

• auto-healing deleted definitions behind the user's back
• changing duplicate-definition semantics
• broader footnote editor UX redesign

Current Findings

• tf.insert.footnote always inserts a reference and only creates the matching definition as a side effect.
• The inline [^ combobox can recreate a missing definition, but only by also inserting another reference.
• Unresolved references already expose package resolution state via api.footnote.isResolved({ identifier }).
• The right seam is a dedicated definition-only transform, then UI repair affordances can call that instead of abusing insert behavior.

Working Plan

• add tf.footnote.createDefinition
• wire unresolved-reference repair UI to the new transform
• cover package and app behavior with focused tests
• update docs/spec/changeset for the new public surface
• run targeted verification only

Progress Log

• 2026-04-06: scoped the feature as explicit unresolved-reference repair, not auto-heal