Compose recomposition performance

Router only — deep fixes live in focused skills below.

Three axes

1. Parameter stability / skipping — can Compose skip this restartable composable; are arguments stable and comparable?
2. Where State is read — is frame-rate State read during composition vs layout/draw?
3. Back-writing across phases — does a later phase write snapshot state that invalidates an earlier phase? Examples: map/list mutation during composition that re-invalidates the same composition; onSizeChanged (layout phase) writing state read by a sibling in composition.

Axes 2 and 3 often overlap (a sibling reading measured size in composition is both a deferred-read violation and a layout → composition back-write). Axis 1 is independent.

Route here → focused skill