Explicit "root" ID Enforcement

[jacobsimionato]

Proposal: Explicit "root" ID Enforcement

Reason

A surface is not valid for rendering until a component with id="root" is defined. Currently, the renderers perform a simple null check, leading to inconsistent "empty" states or flicker while the stream is loading.

Design

1. Ready State: Add an isReady signal to SurfaceModel (or SurfaceComponentsModel) that specifically tracks the presence of the root ID.
2. Progressive Feedback: Update A2uiSurface to check isReady. While false, it should render a standardized "Loading Surface" state or a shimmer effect.
3. Enforcement: Log a warning if components are added to a surface that has been active for a significant time without a root component, aiding developer debugging.

Key Files

• renderers/web_core/src/v0_9/state/surface-model.ts
• renderers/react_prototype/src/A2uiSurface.tsx