lingxia-surface 0.15.0

Core surface presentation primitives (roles, kinds, positions) for the LingXia framework
Documentation

lingxia-surface — the platform-agnostic core of the Adaptive Surface Layout model (see docs/internal/shell-ui-spec.md).

Pure Rust, no UI: the Surface Graph, its invariants and state transitions, the two-axis derivation into DerivedLayout, and the Host arbitration pure function. Each platform skin binds the DerivedLayout output.