Add HyperFrames skills

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011h6NB8JQtfPc6eRCefEzBB

.agents/skills/faceless-explainer/scripts/lib/assets.mjs

@@ -0,0 +1,56 @@
+// assets.mjs — stage frame-named capture assets into assets/.
+// Shared by stage-assets.mjs (Step 4 close, BEFORE the frame workers run) and
+// assemble-index.mjs (Step 5, idempotent backstop). Only assets a frame names
+// in `asset_candidates` are staged; unnamed assets never reach the project.
+// asset_candidates value form: "assets/<basename> — desc; assets/… — …".
+
+import { copyFileSync, existsSync, mkdirSync } from "node:fs";
+import { basename, join } from "node:path";
+
+export function basenamesFromCandidates(value) {
+  if (typeof value !== "string") return [];
+  return value
+    .split(";")
+    .map((seg) => seg.split(/\s+[—–-]\s+/)[0].trim()) // strip the " — description"
+    .filter(Boolean)
+    .map((p) => basename(p.replace(/^assets\//, "")));
+}
+
+// Copy each frame's asset_candidates from capture/{assets,assets/videos,
+// assets/svgs, screenshots} into assets/. Already-staged files are left as is
+// (first-wins), so calling this twice is safe. Returns { staged, wanted, anomalies }.
+export function stageAssets({ hyperframesDir, frames }) {
+  const wanted = new Set();
+  for (const f of frames) {
+    for (const b of basenamesFromCandidates(f.extra?.asset_candidates)) wanted.add(b);
+  }
+  const captureDirs = [
+    join(hyperframesDir, "capture/assets"),
+    join(hyperframesDir, "capture/assets/videos"), // videos download into a subdir
+    join(hyperframesDir, "capture/assets/svgs"), // inline SVGs extract into a subdir
+    join(hyperframesDir, "capture/screenshots"),
+  ];
+  const assetsDir = join(hyperframesDir, "assets");
+  const anomalies = [];
+  let staged = 0;
+  if (wanted.size > 0) {
+    mkdirSync(assetsDir, { recursive: true });
+    for (const b of wanted) {
+      const dest = join(assetsDir, b);
+      if (existsSync(dest)) {
+        staged++;
+        continue;
+      } // first-wins / already staged
+      const src = captureDirs.map((d) => join(d, b)).find((p) => existsSync(p));
+      if (src) {
+        copyFileSync(src, dest);
+        staged++;
+      } else {
+        anomalies.push(
+          `asset "${b}" named by a frame but not found under capture/ — frame will 404 it`,
+        );
+      }
+    }
+  }
+  return { staged, wanted, anomalies };
+}