LLM-State Contract — Schema Agreement Between App and AI

[leoafarias]

Is your feature request related to a problem? Please describe.
There is no agreement between app and AI about state structure. The LLM receives widget schemas but not a state manifest, so it guesses paths, can create arbitrary ones, and can vary paths between turns. Ownership of state structure (app vs. AI) is undefined.

Describe the solution you'd like
A defined state contract: a discoverable schema/manifest of allowed paths, plus guidance on ownership. Preferably, app state is the source of truth and DataModel is a derived view, with validation for path creation.

Describe alternatives you've considered
Letting the LLM create state freely, or constraining via prompt-only guidance. Both lead to brittle results (non-reactive UIs, invented paths, or inconsistent regeneration).

Additional context
Discussion: #609

[yjbanov]

An agreement system between the app and the AI on data structure, but also read/write permissions, makes sense. Treating app state as the source of truth with DataModel being a derived view is an interesting idea. I can actually see this extending into a wider "BusinessModel" containing both data and business logic (actions/events), with structure and rules defined in a way that's easy to describe to the LLM (like we do for the widget catalog) and, crucially, easy to enforce (e.g. as part of upholding the required trust model and/or as protection for certains kinds of hallucinations).