docs(product-launch-video): catch motion jumps at frame cuts

skills/product-launch-video/SKILL.md

@@ -126,6 +126,8 @@ Read `references/visual-design.md`, `../hyperframes-animation/blueprints-index.m
 
 For every visual frame, write a **time-coded shot sequence** into `STORYBOARD.md` per `visual-design.md`'s method: pick the frame's blueprint (or compose), instantiate it with THIS product's content, and pace each Scene's reveal to the voiceover so the frame develops across its full duration instead of front-loading then freezing. State layout and motion **inline** per Scene (vocabularies in `visual-design.md` and `motion-language.md`). Add one video-wide `## Video direction` block.
 
+When an element visibly continues across a frame boundary, give both workers the same numerical handoff in `STORYBOARD.md`: add `handoff_out:` to the outgoing frame and a matching `handoff_in:` to the incoming frame. Name the element and its exact x/y position, scale, opacity, and motion direction/speed at the cut. Omit these fields for a deliberate clean cut. The goal is simple: parallel workers must not invent two different versions of the same seam.
+
 Do not change story, script, asset choices, `asset_candidates`, `transition_in`, or captured source material. Do not write HTML in this step.
 
 Stage named assets after visual design is locked:
@@ -186,9 +188,9 @@ Inject transitions, run checks, pause for review, then render.
 
 `npx hyperframes check`
 
-`npx hyperframes snapshot --at <frame-midpoints>`
+`npx hyperframes snapshot --at <frame-midpoints-and-each-cut-minus-0.1s-and-plus-0.2s>`
 
-`snapshot` stitches the captured frames into one contact sheet (`snapshots/contact-sheet.jpg`). Glance at it; if nothing is obviously broken, move on — don't linger here.
+`snapshot` stitches the captured frames into one contact sheet (`snapshots/contact-sheet.jpg`). Inspect the midpoint frames for layout failures, then compare the two images around every cut. A continuing element must keep the promised position, scale, opacity, and direction; fix any visible pop before rendering.
 
 If a command fails, surface stderr and stop — don't pile on recovery commands. Fix it yourself: the cheapest safe edit to `compositions/frames/NN-*.html`, then rerun the failed check.
 

skills/product-launch-video/sub-agents/frame-worker.md

@@ -13,3 +13,7 @@
 **Place each candidate by its `roles`** (the `focal` is the hero): a `cutout` is a foreground subject — respect the 83% keep-out, lay text around it, not over its face; a `background` is full-bleed and dimmed ~30–50% so foreground content stays legible. Frame files are sub-compositions. Audio remains orchestrator-owned: never author `<audio>` in a frame. An approved `[video]` candidate may be declared as a frame-local `<video data-frame-video="approved" data-start="..." data-duration="..." data-track-index="...">`; `assemble-index.mjs` hoists it to the host root and translates its timing. Give every approved video explicit host geometry with numeric `data-frame-video-x`, `data-frame-video-y`, `data-frame-video-width`, and `data-frame-video-height`; optionally set `data-frame-video-fit="cover|contain|fill|none|scale-down"` (default `cover`). The assembler converts only those values to host CSS: frame-local classes and inline styles do not cross the hoist boundary. Do not use this declaration for audio, unapproved URLs, or videos without explicit timing and geometry. If no approved video is supplied, use an explicitly supplied static still/key art (`[video-still]` or another image candidate) as `<img>`; do not extract a frame, fabricate a URL, or silently embed an unapproved clip.
 
 Brand text comes from your frame's `scene` / narrative — never from `frame.md` (a style spec, not the product's content). Place the named assets, and never invent new ones.
+
+## Cross-frame handoffs
+
+If the packet includes `handoff_in:` or `handoff_out:`, treat those values as a hard boundary contract. Start or end the named element at the exact x/y position, scale, opacity, and motion direction/speed provided. Do not restyle or reinterpret that boundary state. The neighboring frame is being built by another worker and will use the matching values.