Nui

Expert guidance for writing frontend code using NuiCpp -- a C++ WebAssembly (WASM) frontend library compiled via Emscripten. Conceptually similar to JSX but expressed entirely in C++. Use this skill whenever the user asks to build UI components, pages, or applications using NuiCpp, Nui, or "C++ frontend/WASM UI". Also trigger when the user mentions Nui::Observed, Nui::range, ElementRenderer, Nui::Elements, Nui::Attributes, StateTransformer, ChangePolicy, ValWrapper, convertToVal, convertFromVal, or any other Nui:: namespace identifiers. Trigger even for partial tasks like "add a button to my Nui component", "how do I handle events in Nui", or "write a function component". This skill covers element syntax, reactive state, range rendering, class components (functor + pimpl), function components, StateTransformer, nil/fragment, WebAPI event wrappers, val conversion, JS interop via emscripten::val, and reactive side-effects via listen/smartListen/ListenRemover.