foldkit-bundle

Packages a Foldkit child machine, a Submodel, once, and places it anywhere in a parent, without adding a store, a reducer, or a runtime.

A Submodel in Foldkit is wired by hand in five places: the update fold, the init, the Subscription lift, the Managed Resource lift, and the view. Placing the same child twice repeats all five. A Bundle holds the child's parts in one value, and a Link says where it lives. Placing it compiles each part to the Foldkit lift that already exists for it.

Bundle  (what: Model, Message, init, update, subscriptions, resources, view, helpers)
  +
Link    (where: a lens onto the child Model, and the parent Message variant)
  =
Placed  (the same parts, lifted into the parent)

A placement is still an ordinary Submodel. The child's state is a field of the parent Model, its Messages are a variant of the parent Message, and every transition goes through the parent's update. Replay, DevTools, and Scene tests see exactly what they saw before.