fix(skill): w2h enforcement round 2 — close the deeper shirking patterns

A second agent debrief (different session, with the prior enforcement edits
applied) revealed the most damning failure yet: the agent used 1 of 65
captured assets. They wrote their own "Asset Audit" table saying SKIP for
64 hero illustrations, brand SVGs, and signature visuals. The entire point
of capture is to USE the brand's assets — that gate was bypassed entirely.

The debrief also revealed 5 other patterns the prior enforcement missed.
This commit closes all 6.

**Pattern A — Asset Audit gate (step-3-storyboard.md)** — BIGGEST FIX

Adds a non-skippable Asset Audit section in Step 3 that requires viewing
every page of capture/assets/contact-sheet-*.jpg + svgs/contact-sheet-*.jpg,
pasting 5 distinctive assets per page (with descriptions of what's actually
pictured), and choosing USE/SKIP per asset with one-sentence justification
for each SKIP. Brand-defaults floor: at least one beat MUST use a captured
hero illustration/photograph/signature diagram — not just the logo. The
forbidden list explicitly calls out: reading asset-descriptions.md alone
without opening the contact sheets, and rebuilding signature graphics in
CSS when the brand's own SVG of that graphic is in capture/assets/.

**Pattern B — Auto mode scope (SKILL.md + step-2-brief.md)**

Clarifies that auto mode covers user-PREFERENCE gates (TTS provider,
voice, beat count, captions yes/no — where the agent decides on the
user's behalf) but NOT quality-VERIFICATION gates (Asset Audit, per-beat
HTML read, DoD checklist, honest disclosure). Adds explicit test for
distinguishing: if the answer changes the content of the video, it's a
preference; if the answer is "did the verification happen?", it's a
quality gate. The agent that skipped the captions question by reasoning
"auto mode says bias toward action" was misusing auto mode.

**Pattern C — 3-path audio/motion verification (step-6-validate.md)**

Replaces the prior "Path 1 or explicit deferred" with three explicit
paths: (1) Play preview in Playwright, (2) render low-res MP4 and read
frames at ≥5fps, or (3) explicit deferred disclosure with QUANTIFIED
coverage gap ("18/900 frames = 2% coverage"). The percentage in Path 3 is
mandatory — vague "deferred to user" was the loophole. Forbidden: claiming
"confirmed via snapshot" as audio/motion evidence; 18 PNGs from a 900-
frame video is 2% coverage, not verification.

**Pattern D — Sub-agent diagnoses are hypotheses (beat-builder-guide.md)**

When a sub-agent reports "this is a linter false positive" / "this is a
known bug", that is a HYPOTHESIS from one symptom — not a verified
finding. Before propagating the workaround to other beats, main agent
must EITHER read the source to confirm OR explicitly disclose the
unverified claim. The debrief showed the main agent applied beat-2's
"linter false positive" diagnosis to beat-4 without ever reading
packages/core/src/lint/utils.ts to confirm.

**Pattern E — Re-snapshot after parallel sub-agents (step-5-build.md)**

When sub-agents run in parallel, each snapshots a project where sibling
beats may not exist yet. Their snapshots at beat boundaries or during
shader transitions show the WRONG content (typically previous beat).
Required after all complete: a canonical project-wide snapshot via the
CLI — that's what Step 6's DoD uses. Sub-agents' intermediate snapshots
are sanity checks, not the deliverable.

**Pattern F — STORYBOARD.md must be updated when divergence accepted
(beat-builder-guide.md)**

When a sub-agent diverges from spec ("the real brand mark is lowercase
'huly' not uppercase 'HULY'") AND the main agent accepts the divergence,
the main agent MUST patch STORYBOARD.md to reflect reality. Otherwise
the spec lies and the next session reading it as ground truth gets the
wrong information. Examples covered: brand mark casing, cell size at
scale, SFX timing alignment.

6 files changed, +131/-11 (net +120 lines of enforcement).
Format checks pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

skills/website-to-hyperframes/references/step-5-build.md

@@ -389,6 +389,22 @@ For every `.html` file in `compositions/`, confirm that `index.html` has a `data
 
 **Captions stub rule:** Never create a `compositions/captions.html` with an empty transcript (`const script = [];`). If the VO/transcript step was skipped or failed, do not create the captions composition at all. An empty captions file that returns immediately is worse than no captions file — it silently does nothing and wastes a track slot.
 
+### Parallel sub-agent snapshots are stale — re-snapshot after all complete
+
+When you dispatch sub-agents in parallel (one per beat), each sub-agent snapshots a project where sibling beats may not exist yet. Their per-beat snapshots are valid for THEIR beat in isolation, but **any snapshot at a beat boundary or during a shader transition will show the wrong content** — typically the previous beat's content because the next beat hasn't been built.
+
+Example: Beat 6's sub-agent took a snapshot at t=25.7s and saw Beat 1's content because Beat 5 didn't exist yet when Beat 6's sub-agent ran. The sub-agent reported this as "shader transition behavior showing previous scene" — a plausible-sounding but wrong diagnosis.
+
+**Required after all sub-agents complete:**
+
+```bash
+node /<repo-root>/packages/cli/dist/cli.js snapshot <project-dir> --frames <N>
+```
+
+where N follows the snapshot formula: `max(beats × 3, ceil(duration_seconds / 2))`. This is the canonical snapshot that Step 6's DoD uses — not any individual sub-agent's intermediate snapshots.
+
+Sub-agents' snapshots are still useful as per-beat sanity checks, but they are not the deliverable. The post-completion snapshot is. Don't skip it because "the sub-agents already snapshotted."
+
 ## 5. Read each beat HTML top-to-bottom — REQUIRED gate before Step 6
 
 **This gate is non-skippable.** "I read it and it looks fine", "the sub-agent confirmed", "the snapshots look right" are NOT acceptable. Snapshots are 3 frames out of 300+ in motion — they hide everything that goes wrong between them.