Suspense boundary

The slow component below is wrapped in <webjs-suspense>. Its fallback shows on the first byte and the resolved content streams in when the slow await settles. Reload to see the fallback, then the fact stream in.

.fallback is a property hole (unquoted, per invariant 4). Contrast with the async render demo, where SSR blocks so the data is in the first paint with no fallback.