Declares extensions?: readonly Extension[] (@codemirror/state) on the shim's
props; the existing prop spread forwards it to @plannotator/markdown-editor,
which threads it into the atomic-editor engine. This is the seam Workspaces
needs to install wikiLinks(...) and, later, y-codemirror.next collab bindings
without importing the engine directly.
The doc comment carries the consumer-required rider prominently: the engine
captures the array ONCE per documentId — swapping the array later is silently
ignored until remount; config callbacks may close over live state.
Test mounts through the SHIM with a facet-based probe extension
(EditorView.editorAttributes) and asserts the attribute lands on the engine's
.cm-editor DOM, proving the seam end-to-end, plus byte-fidelity is untouched.
Michael Ramos