hyperframes-studiolisted

# HyperFrames Studio conventions Studio draws one timeline row per top-level element. A project that follows the rules below opens as a short, readable timeline; one that does not opens as a wall of unlabeled rows the user cannot edit. These are conventions for what to build. For how to change a clip, follow `/hyperframes/hyperframes-core` `references/creator-editing-recipes.md` and never invent a different form of the same edit. ## 1. Every scene is a sub-composition The root composition holds only timed hosts, media and audio. Any scene with nested structure (a div containing children, a title with a subtitle, a chart) is its own file loaded with `data-composition-src`, wiring in `references/sub-compositions.md`. Nested markup left inside the root does not become a row of its own. It hides inside one opaque row that cannot be trimmed or moved part by part. Author as if a structure lint rejects any violation. ## 2. One caption track - All captions live on one track: a single sub-composition host (one `data-track-index`) marked `data-track-kind="captions"` that carries every caption group in order. - Never one row per caption group, and never captions mixed onto a track with another kind. - Word-timing rules are unchanged: see `/hyperframes/embedded-captions` and the `caption_*` lint rules. ## 3. One element kind per track Group by kind so each row is one thing the user can select, mute or drag as a set. | Kind | `data-track-ki