Hero gate refuses while a produced plate is unreferenced by the source

The first live run produced a faithful carburetor plate, then drew the
region in SVG and left the plate on disk. Before diffing, the hero gate
now walks the artifact (or a bounded source tree) for every plate's file
name or a data URI named for it.

AI-assisted (Claude).

Co-Authored-By: Claude <noreply@anthropic.com>

skill/reference/new-work.md

@@ -102,7 +102,7 @@ Then, in order, each closed by `node {{scripts_path}}/build-phase.mjs advance` (
 
 1. **spec.** Measure the comp: `comp-spec.mjs --comp <comp> --grid` writes a coordinate grid over the comp; open it, name every salient region by grid span in a regions file (kind `plate` / `image` / `texture` for anything painted: every illustration, photograph, figure, product object, and material texture; `text` / `control` / `chrome` for what code draws), and run `comp-spec.mjs --comp <comp> --regions <file>`. The spec carries each region's box, sampled palette, and medium; `comp-spec.mjs --print` is the build's reference from here on. Anything not in the spec does not exist on the page: no borders, rules, containers, or chrome the comp does not show. Only three concessions exist: fonts (the closest obtainable face), icons (exact match unless the user chose an icon library), and genuine defects in the comp such as spelling errors. <!-- rule:skill-comp-spec -->
 2. **plates.** Every raster region ships as a plate: the region regenerated at asset resolution from its comp crop, UI text removed, at its `plate` path. `generate-image.mjs --plate <id>` does one region end to end and scores it against the crop; a harness-native image tool takes the crop (`comp-spec.mjs --crop <id>`) as its input image and `comp-spec.mjs --plate-prompt <id>` as its prompt, then `embed-prompt.mjs`. With parallel subagents, spawn the shipped asset producer (`impeccable-asset-producer`; `impeccable_asset_producer` in codex; `/impeccable-asset-producer` in Cursor; on GitHub Copilot say "Use the impeccable-asset-producer agent") with the spec path and let it produce them all; without subagents, produce them here. A crop of the comp is a reference, never a shipping pixel. The gate checks every plate exists, is at least 1.5x the region's size, and reads as the region. Page code waits for this gate: a page written before its plates exist is a page that draws its material in CSS. A single-file deliverable changes nothing here: the plate is produced the same way and inlined as a data URI. `--force` exists for one case only, the user downgrading the comp's authority in words you quote in `--reason`; the script refuses every other reason. <!-- rule:skill-plates-before-page -->
-3. **hero.** Build only the first viewport, at the comp's own dimensions, from the spec's boxes, palette, and plates; capture it into `.impeccable/review/hero-repro.png` at those dimensions; advance. The gate runs `comp-diff.mjs`, writes `.impeccable/review/diff/hero/` (side-by-side, heatmap, one paired crop per region, `report.json`), and passes at 72% overall with no region missing. When it fails, open the side-by-side and the worst region pairs it names, fix those regions, recapture, and advance again; the numbers rank, the crops decide. This is where the run's ambition is won or lost, and a retry here costs minutes where a rebuild verdict at the finish costs the run. <!-- rule:skill-hero-gate -->
+3. **hero.** Build only the first viewport, at the comp's own dimensions, from the spec's boxes, palette, and plates (every plate placed in the markup: an `<img>`, a background image, or an inlined data URI named for it); capture it into `.impeccable/review/hero-repro.png` at those dimensions; advance. The gate first refuses while any plate is unreferenced by the source, then runs `comp-diff.mjs`, writes `.impeccable/review/diff/hero/` (side-by-side, heatmap, one paired crop per region, `report.json`), and passes at 72% overall with no region missing. When it fails, open the side-by-side and the worst region pairs it names, fix those regions, recapture, and advance again; the numbers rank, the crops decide. This is where the run's ambition is won or lost, and a retry here costs minutes where a rebuild verdict at the finish costs the run. <!-- rule:skill-hero-gate -->
 4. **sections.** Build the rest of the surface inside the spec's system: the same corner language, line weights, and palette, and nothing the comp never shows. Where the comp does not cover a region, it inherits the recorded system.
 5. **motion.** The signature interaction, reveals, and motion, orchestrated once rather than scattered.
 6. **responsive.** The other viewports. A comp'd surface that is mobile-first was comped portrait; the plates were produced for that frame.