docs(product-launch-video): point the scroll shot at the plate, make handoff fields binding

Two follow-ups from the same end-to-end runs, now that #2880 and #2881 have landed and
their sentences exist to edit.

**The scroll shot pointed at an artifact that did not exist.** #2881 said "use a 2x
full-page capture and animate the viewport over it". Neither half held: capture emitted
no full-page image, and 2x on a long marketing page passes Chrome's 16384px screenshot
cap precisely on the pages that most want a scroll shot. Both runs watched the agent go
looking, not find it, and improvise — once by re-capturing 2x strips per section, once by
using the native 1920x1080 tiles full-bleed. This PR's capture commit adds the 1x plate,
so the sentence can now name something real: the plate, its absence on pages too tall to
capture in one piece, the tile fallback, and why pushing in past 1:1 still wants a region
capture of its own.

**A constant field was being read as an absent one.** #2880 asks for x/y, scale, opacity
and direction/speed on every handoff. Across two runs on the same model, `opacity` went
0/12 then 12/12 — when the value never changes, leaving it out is a reasonable reading of
the instruction. But downstream an omission and "there is no handoff here" are the same
thing, so the field set has to be stated as binding even when constant. Same clause added
to the worker's side of the contract.

Validation: `bun run lint:skills`

Author: WaterrrForever

skills-manifest.json

@@ -62,7 +62,7 @@
       "files": 29
     },
     "product-launch-video": {
-      "hash": "6f2b690d22392425",
+      "hash": "ead12de8df2ed55d",
       "files": 26
     },
     "remotion-to-hyperframes": {

skills/product-launch-video/SKILL.md

@@ -54,7 +54,7 @@ Classify the input and choose the path. Explicit URL -> capture it and use the s
 
 Run capture with: `npx hyperframes capture "<URL>" -o ./capture`
 
-For a site tour or show-it-as-is brief, the captured page is the visual source of truth. Use the real screenshot instead of rebuilding the full website in HTML. If the shot needs internal movement, keep the screenshot as the base and overlay real captured assets at measured positions, or rebuild only the one component that moves. For a scroll shot, use a 2x full-page capture and animate the viewport over it. Recreate the whole page only when the user explicitly asks for a stylized interpretation or the capture is unusable.
+For a site tour or show-it-as-is brief, the captured page is the visual source of truth. Use the real screenshot instead of rebuilding the full website in HTML. If the shot needs internal movement, keep the screenshot as the base and overlay real captured assets at measured positions, or rebuild only the one component that moves. For a scroll shot, animate the viewport over `capture/screenshots/full-page.png` — the 1x plate of the whole document, pixel-exact for a 1920-wide viewport travelling down it. It is absent when the page was too tall to capture in one piece; fall back to the overlapping scroll-position shots in the same directory. Pushing in past 1:1 wants its own 2x capture of that region instead, since the plate has no headroom above 1x. Recreate the whole page only when the user explicitly asks for a stylized interpretation or the capture is unusable.
 
 If `GEMINI_API_KEY`, `GOOGLE_API_KEY`, or an OpenRouter key exists, capture auto-captions assets into `capture/extracted/asset-descriptions.md`. This is not a review gate. Without a vision key, use DOM context and continue.
 
@@ -128,7 +128,7 @@ 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.
+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 — state every field even when it does not change, because a constant is `opacity: 1`, not an omission. Omit the whole block only 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.
 

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

@@ -18,4 +18,4 @@ Brand text comes from your frame's `scene` / narrative — never from `frame.md`
 
 ## 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.
+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; a field the packet states as unchanged is still binding, not optional. Do not restyle or reinterpret that boundary state. The neighboring frame is being built by another worker and will use the matching values.