v0.3.8 Status surfaces

Pages

• State UI concept - Dedicated BusDK UI framework concept page for State.
• UI color and status - BusDK UI design rule for semantic color and status meaning.
• Library status surfaces - BusDK UI library status, empty, loading, result, and error surface contract.
• StatusPill UI component - Dedicated BusDK UI reference for StatusPill.
• EmptyState UI component - Dedicated BusDK UI reference for EmptyState.
• LoadingState UI component - Dedicated BusDK UI reference for LoadingState.
• ErrorBanner UI component - Dedicated BusDK UI reference for ErrorBanner.
• ResultPanel UI component - Dedicated BusDK UI reference for ResultPanel.