UseStreamReturn

Svelte binding return type for useStream. Reactive projections are exposed as getters on a stable object so templates can read stream.messages directly without a .value / .current hop and $derived wrappers auto-track the getter read.

Destructuring (const { messages } = stream) breaks reactivity — this is a Svelte 5 constraint and applies to every getter-object pattern. Access fields through the live stream handle instead.