frames.sx: ReactiveResetFrame + DerefFrame constructors,
kont-capture-to-reactive-reset, has-reactive-reset-frame?.
cek.sx: deref as CEK special form, step-sf-deref pushes DerefFrame,
reactive-shift-deref captures continuation as signal subscriber,
ReactiveResetFrame in step-continue calls update-fn on re-render.
adapter-dom.sx: cek-reactive-text/cek-reactive-attr using cek-run
with ReactiveResetFrame for implicit DOM bindings.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>