A2 — element-handoff

Composes

• element-handoff (the primary effect — a sharedLayer with keyframes)
• bg-swap (the scene change underneath)

Note on scope

A2 is not a standalone scene archetype in the sense of "this scene contains a handoff" — it describes the transition between two A1 (or other) scenes that share a continuity element. The impl-brief atom treats it as a transition spec applied at scene boundaries, not as a scene's primary content.

When the storyboard declares transitions[i] = A2-element-handoff, that means the continuity element animates across the boundary between scene[i] and scene[i+1].

Layout