Slideshow authoring contract

A HyperFrames slideshow is a normal HyperFrames composition — scenes, clips, GSAP timelines — with one extra ingredient: a JSON island that declares which scenes are slides and how they connect. The player's SlideshowController reads the island and turns the continuous GSAP timeline into a discrete, navigable deck.

Read /hyperframes-core first for the base composition contract (clips, tracks, data-* attributes, determinism rules). This skill covers only what is new: the island schema, slide writing rules, fragments, branching, validation, and the wrapping component.

The two pieces

1. Scenes — declared the normal way

Every slide is backed by a scene. Declare scenes with data-composition-id, data-start, data-duration, and data-label: