AnyStream

Erased handle useful as a parameter type for helper components that pass a stream through to selector primitives without reading values directly. Mirrors the React/Vue AnyStream alias.

Widening the generic slots to any is not enough on its own: members computed from T in covariant positions don't collapse to a top type under any. toolCalls resolves to Signal<AssembledToolCall<…, never>[]> — the never output slot is narrower than a concrete handle's …, unknown, so a fully-typed useStream<typeof agent>() handle would fail to assign and every injectToolCalls(stream) call would need an as AnyStream cast. Override toolCalls / values (keeping the Signal wrapper) with their widest forms so the erased handle is a true supertype of every concrete UseStreamReturn.