v0.2.0

Added

• SkeletonContainer(state, dataOrNull, isFailure, onFailure, content) — a
  state-driven overload for sealed/state-based loading (e.g. a
  Loading/Success/Failure state), deriving loading and a typed
  success payload from the caller's own state instead of a plain
  Boolean, with a dedicated onFailure slot. Demonstrated in the sample
  app via StateDrivenPostCard.