A reference-mode bus instance — one shared point/show state and its subscribers. The store is a
first-class value (not a module global) so a client can mount its OWN bus above a subtree via
ReferenceModeProvider: their custom picker widget and the Studio/Workbook under the same
provider share that instance, making a third-party producer first-class with no Studio
involvement. Everything below the provider — layers, header layers, inputs, the keymap hosts —
resolves the store through useReferenceMode/useReferenceModeStore.
A reference-mode bus instance — one shared point/show state and its subscribers. The store is a first-class value (not a module global) so a client can mount its OWN bus above a subtree via ReferenceModeProvider: their custom picker widget and the Studio/Workbook under the same provider share that instance, making a third-party producer first-class with no Studio involvement. Everything below the provider — layers, header layers, inputs, the keymap hosts — resolves the store through useReferenceMode/useReferenceModeStore.