fix(skills,cli): close four reproduced contract gaps from the CLI feedback digest (#2476)

* fix(cli): invalidate the skills nudge cache after a successful install/update/check

The passive "N skills out of date or missing" nudge reads a 24h config
cache that only the background check (on non-skills commands) ever wrote.
The skills commands themselves are excluded from the nudge pipeline, so a
successful `skills update`/install/check never refreshed or dropped the
cached verdict — the pre-install count kept printing on every other
command for up to 24h.

Reconcile commands now drop the cached verdict (counts + timestamp) so
the next command's background check re-runs for real. The offline
presence-only path deliberately keeps the cache: that run learned nothing
about freshness.

* fix(skills): win32-safe npx spawns in media-use + accurate whisper wording

The Whisper transcribe fallback and the Kokoro local-TTS delegation both
spawned a bare "npx" via execFileSync — on Windows npx is npx.cmd, which
spawn cannot exec, so both paths died with `spawnSync npx ENOENT`. Route
them through the skill's existing resolveSpawnCommand (node + npx-cli.js
on win32, no shell:true), same as the audio engine's TTS spawns.

Also corrects the "bundled with the hyperframes CLI" claim about
whisper.cpp: it is resolved from PATH / installed via Homebrew / built
from source with git+cmake on first use, and models download from
HuggingFace — nothing whisper is shipped in the package.

* feat(skills): canonical fully-silent marker + auth status exit-code docs

product-launch's Step 3.1 gate said "or the project is marked silent"
but nothing defined how to mark one, and audio.mjs unconditionally
retrieved BGM. Define the canonical marker — `music: none` in the
storyboard's top YAML block, plus no SCRIPT.md — and honor it:
audio generate produces nothing (removing stale audio_meta.json, since
absence is what assemble treats as silent), and `music: none` with
narration keeps TTS while turning BGM off.

Also documents the `auth status` exit-code contract (exit 1 while
signed out is the normal offline state, not a failure) in the
product-launch Step 0 note and the CLI skill's cloud reference.

* fix(skills): transient-init retry for standalone animation-map and contrast-report

The standalone helpers called initializeSession exactly once, so a valid
modular project — whose sub-composition timelines register asynchronously
— could hit the readiness deadline and die with the transient
"zero duration / Runtime ready: false" diagnostic the render pipeline
retries (probeStage). Add initializeSessionWithRetry to the shared
package-loader (both byte-identical copies): close the crashed session
and retry once with a fresh browser, gated by the engine's canonical
isTransientBrowserError — now re-exported from @hyperframes/producer,
with a frozen fallback pattern list for older published packages. The
"Runtime ready: true" fast-fail (a genuine authoring bug) still fails
without a retry.

* feat(skills): extend the fully-silent marker to faceless-explainer and pr-to-video

Both workflows reuse product-launch's audio model — their Step 3.1 gates
carried the same undefined "marked silent" phrase, and their (intentionally
identical) audio.mjs copies had the same unconditional BGM retrieve. Port
the `music: none` marker handling into both copies, define the marker in
their SKILL.md Step 3.1 and story-design references, and turn the
copies' "intentionally identical" header claim into a byte-identity pin
test so the next fix can't silently miss one of them.

* test(cli): reset the prune mock explicitly instead of relying on restoreAllMocks

The converge test's toHaveBeenCalledTimes(1) held only because vitest 3's
vi.restoreAllMocks() clears vi.fn() call state; vitest 4 restores spies
only, so the count would accumulate across tests and fail. Reset
pruneOrphanedLockEntries in beforeEach like the other manifest mocks —
passes under both vitest 3.2.4 (pinned) and vitest 4.

* test(skills): close review findings — package-loader pin, whisper win32 parity, quoted-none

Review follow-ups on #2476:

- package-loader.mjs byte-identity pin (the elevated concern): the two
  copies now carry initializeSessionWithRetry + FALLBACK_TRANSIENT_PATTERNS,
  exactly the shared-logic shape a future fix could land in one copy and
  miss in the other — same enforcement as the audio.mjs pin.
- whisper win32 call-site parity: runWhisper's npx resolution lifted into
  lib/npx-sync.mjs (resolveNpxInvocation, injectable params matching the
  localTtsGenerate idiom) with the same three-branch coverage as the
  Kokoro site — plus the hard-fail contract (throws actionably, since the
  whisper fallback has no next provider to fall through to).
- quoted music: "none" pin: the vendored storyboard parser strips matching
  quotes at parse time (stripQuotes), so the silent marker already accepts
  the quoted spelling — pinned so that stays true.

skills/media-use/scripts/lib/tts-local-provider.mjs

@@ -2,6 +2,7 @@ import { execFileSync } from "node:child_process";
 import { existsSync, statSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
+import { resolveSpawnCommand } from "../../audio/scripts/lib/tts.mjs";
 
 // Local voiceover via the packaged Kokoro-82M TTS (the `hyperframes tts` CLI),
 // the free/private default now that HeyGen TTS costs wallet credits. Kokoro runs
@@ -26,17 +27,44 @@ function probeDurationSeconds(file) {
   }
 }
 
-export async function localTtsGenerate(intent, ctx) {
+// `platform`/`execFn`/`env`/`pathExists` params (defaulting to the real
+// values) exist so tests can exercise the win32 branch without mocking
+// node:child_process (its ESM exports are non-configurable) — same idiom as
+// spawnP in ../../audio/scripts/lib/tts.mjs.
+export async function localTtsGenerate(
+  intent,
+  ctx,
+  platform = process.platform,
+  execFn = execFileSync,
+  env = process.env,
+  pathExists = existsSync,
+) {
   const outPath = join(tmpdir(), `media-use-kokoro-${process.pid}-${Date.now()}.wav`);
   const argv = ["hyperframes", "tts", intent, "--output", outPath];
   if (ctx?.voice) argv.push("--voice", ctx.voice);
   if (ctx?.lang && ctx.lang !== "en") argv.push("--lang", ctx.lang);
+  // On Windows a bare "npx" is npx.cmd, which execFileSync cannot exec
+  // (spawnSync npx ENOENT) — resolveSpawnCommand reroutes it through
+  // node + npx-cli.js, same as the audio engine's TTS spawns.
+  const resolved = resolveSpawnCommand(
+    "npx",
+    argv,
+    { encoding: "utf8", timeout: 300000, stdio: ["ignore", "pipe", "pipe"] },
+    platform,
+    env,
+    pathExists,
+  );
+  if (!resolved) {
+    // npx-on-win32 with no resolvable npx-cli.js — same terminal condition
+    // spawnP warns about. Fall through to the next provider rather than crash.
+    console.error(
+      "media-use: local voice not enabled (kokoro). Cannot run npx on Windows: " +
+        "npm's npx-cli.js was not found (install npm with Node, or run via npx/npm run so npm_execpath is set).",
+    );
+    return null;
+  }
   try {
-    execFileSync("npx", argv, {
-      encoding: "utf8",
-      timeout: 300000,
-      stdio: ["ignore", "pipe", "pipe"],
-    });
+    execFn(resolved.cmd, resolved.args, resolved.opts);
   } catch (err) {
     // `hyperframes tts` prints its "kokoro-onnx not installed" hint to stdout
     // (clack UI), so read both streams and surface the actionable enable-command