defisland expressions in the render tab are now evaluated through
render-to-dom inside with-island-scope, producing real DOM with signal
bindings. The rendered output persists in a stable container managed by
an effect, outside the reactive render tree.
Known limitation: signal subscriptions don't fire on button clicks yet —
the reactive wiring needs investigation into how deferred (setTimeout)
execution contexts interact with CEK signal tracking. Static rendering
(initial values) works correctly.
Also: removed stale effect that attempted hydrate-island approach.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>