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/cli/src/commands/render.ts

@@ -661,6 +661,30 @@ export default defineCommand({
       }
     }
 
+    // ── Slideshow guard ───────────────────────────────────────────────────
+    // A slideshow deck is several top-level scene compositions with no master
+    // root. `render` captures only the FIRST composition, so a deck renders as a
+    // silently truncated MP4 (e.g. slide 1 of a 40s deck). Warn and point at the
+    // deck-native path. Best-effort — never block a render on this probe.
+    if (!quiet) {
+      try {
+        const renderTarget = entryFile ? resolve(project.dir, entryFile) : project.indexPath;
+        const { slideshowIslandRegex } = await import("@hyperframes/core/slideshow");
+        if (slideshowIslandRegex("i").test(readFileSync(renderTarget, "utf8"))) {
+          console.log(
+            c.warn("⚠") +
+              "  This composition carries a slideshow island — `render` captures only the first" +
+              " scene, so the MP4 will be truncated to slide 1. Use " +
+              c.accent("hyperframes present") +
+              " for the deck; a linear main-line MP4 export is not yet available.",
+          );
+          console.log("");
+        }
+      } catch {
+        /* best-effort — a missing/unreadable target surfaces later in the real flow */
+      }
+    }
+
     // ── Print render plan ─────────────────────────────────────────────────
     if (!quiet && !batchPath) {
       const workerLabel =