fix(media-use): create the output dir before ElevenLabs TTS writes

The ElevenLabs provider spawns a Python helper that writes straight to wavAbs
via a bare open(), which (unlike heygen/kokoro) never creates the parent dir —
so on a fresh project the save throws ENOENT and the line is silently dropped
as 'TTS failed - omitted'. mkdir -p the dir first, guarded so a mkdir failure
(EACCES/EROFS) returns { ok:false } like the rest of the branch rather than
throwing. (Migrated from #1960, whose skills/hyperframes-media path was retired
into skills/media-use; the bug moved with it.)

skills/media-use/audio/scripts/lib/tts.mjs

@@ -239,6 +239,18 @@ export async function synthesizeOne({
 }) {
   if (provider === "heygen") return synthesizeHeygen({ text, voiceId, lang, speed, wavAbs });
   if (provider === "elevenlabs") {
+    // The Python helper writes straight to wavAbs; unlike heygen (transcodeToWav)
+    // and kokoro (the `hyperframes tts` CLI), it does NOT create the parent dir,
+    // so on a fresh project (no assets/voice/ yet) the save fails and the line is
+    // silently dropped as "TTS failed - omitted". Create it first, like the other
+    // providers do. Guarded so a mkdir failure (EACCES/EROFS) returns
+    // { ok:false } like the rest of this branch rather than throwing (the
+    // function's contract is "never throws; failures return { ok:false }").
+    try {
+      mkdirSync(dirname(wavAbs), { recursive: true });
+    } catch {
+      return { ok: false, words: null };
+    }
     const { cmd, args } = pythonInvocation([
       "-c",
       ELEVENLABS_PY,

skills/media-use/audio/scripts/lib/tts.test.mjs

@@ -1,9 +1,9 @@
 import { test } from "node:test";
 import assert from "node:assert/strict";
-import { mkdtempSync, writeFileSync, chmodSync, rmSync } from "node:fs";
-import { join } from "node:path";
+import { mkdtempSync, writeFileSync, chmodSync, rmSync, existsSync } from "node:fs";
+import { join, dirname } from "node:path";
 import { tmpdir } from "node:os";
-import { parseFfmpegDurationBanner, ffprobeDuration } from "./tts.mjs";
+import { parseFfmpegDurationBanner, ffprobeDuration, synthesizeOne } from "./tts.mjs";
 
 test("parseFfmpegDurationBanner reads ffmpeg's stderr Duration line", () => {
   const stderr = [
@@ -64,3 +64,26 @@ test("ffprobeDuration returns NaN when neither ffprobe nor ffmpeg resolve", () =
     rmSync(dir, { recursive: true, force: true });
   }
 });
+
+test("synthesizeOne(elevenlabs) creates the output dir before writing", async () => {
+  const dir = mkdtempSync(join(tmpdir(), "tts-el-mkdir-"));
+  const wavAbs = join(dir, "assets", "voice", "line-0.wav"); // nested, not yet created
+  const savedKey = process.env.ELEVENLABS_API_KEY;
+  try {
+    // Unset the key so the Python side fails fast — the mkdir must run before
+    // the spawn regardless, which is what this guards.
+    delete process.env.ELEVENLABS_API_KEY;
+    await synthesizeOne({
+      provider: "elevenlabs",
+      text: "hi",
+      voiceId: "v",
+      wavAbs,
+      hyperframesDir: dir,
+    });
+    assert.ok(existsSync(dirname(wavAbs)), "output directory should be created");
+  } finally {
+    if (savedKey === undefined) delete process.env.ELEVENLABS_API_KEY;
+    else process.env.ELEVENLABS_API_KEY = savedKey;
+    rmSync(dir, { recursive: true, force: true });
+  }
+});