fix: storyboard-angle review follow-ups (M1 bg-on-clip, B3 slideshow, parser guard, CLI fixes) (#1791)

* fix(skills): storyboard review — bg-on-clip rule, slideshow output, parser parity guard

Addresses the storyboard-angle review (jrusso1020):

- M1 (invisible text): frame-worker.md (x3) + SKILL.md Step 5 (x3) now require a
  frame's full-bleed background on a class=clip layer, never the #root /
  data-composition-id element (the root is clip-gated to its scene window, so a
  background on it is not a dependable ground and dark text can land on the black
  host body). The assembler already paints frame.md's canvas onto index #root as
  the base ground; the per-frame clip rides on top.
- B3 (slideshow truncates to slide 1): slideshow/SKILL.md gains an Output section
  (decks render via 'present'; 'render index.html' captures only the first
  composition; linear main-line MP4 export is deferred).
- Parser drift: vendoredParity.test.ts guards the three vendored storyboard.mjs
  copies (byte-identical + parse-parity with @hyperframes/core).
- skills-manifest.json regenerated for the edited SKILL.md files.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(cli): storyboard review — lint, validate help, snapshot, inspect, capture, render

Addresses the CLI findings from the storyboard-angle review (jrusso1020):

- lint (@hyperframes/lint): accept vendor-prefixed system-font keywords
  -apple-system / BlinkMacSystemFont so a system stack with a generic fallback no
  longer trips font_family_without_font_face (+ test).
- help: list 'validate' under Project in 'hyperframes --help' (was runnable but
  undocumented).
- snapshot: honor -o/--output (the flag did not exist; output was hardcoded to
  snapshots/). The dir is resolved once and threaded through capture + contact
  sheet + Gemini.
- snapshot: split font status into loaded / error / unused with a one-line
  summary; only a real 'error' is reported as FAILED (an unrequested @font-face
  is 'unused', not a contradiction with 'loaded').
- inspect: suppress text_occluded across a scene-to-scene crossfade (occluder in
  a different data-composition-id mount while a scene is mid-fade); a same-scene
  or two-settled-scenes overlap still flags.
- inspect: suppress content_overlap between in-flow siblings governed by the same
  flex/grid container (tight stacks / number lockups are layout slop).
- capture: record source resolution (videoWidth/Height) in video-manifest.json
  alongside the DOM display box; consumers size off the source dims.
- render: warn when the target carries a slideshow island (render captures only
  the first scene, so the MP4 is truncated to slide 1; use 'present').

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/core/src/storyboard/vendoredParity.test.ts

@@ -0,0 +1,71 @@
+import { describe, it, expect } from "vitest";
+import { readFileSync } from "node:fs";
+import { fileURLToPath } from "node:url";
+import { parseStoryboard as coreParse } from "./parseStoryboard.js";
+
+// Sync guard for the hand-vendored parser.
+//
+// Each standalone skill ships a plain-JS copy of this parser at
+// scripts/lib/storyboard.mjs — skills install via `npx skills add`, where a
+// script can't reach @hyperframes/core (and the core export is .ts that node
+// can't load). The copies MUST stay in lockstep with core. This test fails the
+// moment they drift, so a parser change can't silently leave the skills behind:
+//   1. every vendored copy is byte-identical to the others, and
+//   2. a vendored copy parses a representative storyboard identically to core.
+// If you change the parser, update every path below in the same commit.
+const VENDORED_RELATIVE = [
+  "../../../../skills/faceless-explainer/scripts/lib/storyboard.mjs",
+  "../../../../skills/pr-to-video/scripts/lib/storyboard.mjs",
+  "../../../../skills/product-launch-video/scripts/lib/storyboard.mjs",
+];
+
+const vendoredUrls = VENDORED_RELATIVE.map((rel) => new URL(rel, import.meta.url));
+
+// Exercises frontmatter (known keys + an unknown global), H2/H3 frame headings,
+// every recognized meta key + an alias (transition / vo / description), an unknown
+// status (warning + stash under extra), an unparseable duration (warning), unknown
+// extra keys, and free-form narrative — the surfaces most likely to drift.
+const SAMPLE = `---
+format: 1080x1920
+message: "Ship it"
+arc: Hook → Proof → CTA
+audience: builders
+campaign: spring
+---
+
+## Frame 1 — Hook
+- duration: 3s
+- status: animated
+- transition: cut
+- vo: "Open cold."
+- src: compositions/frames/01-hook.html
+- poster: 2s
+- effect: shimmer
+
+Open on the promise.
+
+### Beat 2 — Detail
+- duration: four
+- status: glowing
+- description: a quiet hold
+- voiceover: "The payoff."
+
+Land it.
+`;
+
+describe("vendored storyboard parser parity", () => {
+  it("every vendored copy is byte-identical", () => {
+    const bodies = vendoredUrls.map((u) => readFileSync(fileURLToPath(u), "utf8"));
+    for (let i = 1; i < bodies.length; i++) {
+      expect(
+        bodies[i],
+        `${VENDORED_RELATIVE[i]} drifted from ${VENDORED_RELATIVE[0]} — re-vendor it`,
+      ).toBe(bodies[0]);
+    }
+  });
+
+  it("a vendored copy parses identically to core", async () => {
+    const vendored = await import(vendoredUrls[0].href);
+    expect(vendored.parseStoryboard(SAMPLE)).toEqual(coreParse(SAMPLE));
+  });
+});