feat(cli): add tts command for local text-to-speech via Kokoro-82M (#201)

* feat(cli): add `tts` command for local text-to-speech via Kokoro-82M

Adds `hyperframes tts` — generate speech audio locally using Kokoro-82M
(ONNX), no API key needed. Mirrors the transcribe command architecture.

- New command: `hyperframes tts "text" --voice af_heart --output speech.wav`
- 54 voices across 8 languages, ~5x realtime on CPU
- Auto-downloads model (~311 MB) + voices (~27 MB) to ~/.cache/hyperframes/tts/
- Requires Python 3.8+ with kokoro-onnx installed
- Extracted shared `downloadFile` utility from whisper/manager.ts with
  atomic .tmp→rename to prevent partial download corruption
- Added hyperframes-tts skill with voice selection guide
- Updated CLAUDE.md with TTS docs, voice table, and skill reference

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs(tts): improve skill per skill-creator guidelines

- Move trigger info from body to frontmatter description
- Remove `trigger` field (not a valid frontmatter field)
- Remove CLI flag docs Claude can derive from --help
- Remove redundant voice tables (keep content-to-voice mapping)
- Fix composition audio example to use actual <audio> element pattern
- Keep non-obvious workflows: TTS+transcribe for captions, long scripts

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs(tts): add guidance for using external TTS sources

Help users understand when to use cloud TTS (voice cloning, broader
languages, higher quality) vs the built-in Kokoro model, and how
external audio integrates into the same composition workflow.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs(tts): prioritize HeyGen API as recommended cloud TTS

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs(tts): remove external TTS section for now

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix(tts): set required: false on input arg so --list works standalone

Citty treats positional args as required by default unless explicitly
set to required: false. Without this, `hyperframes tts --list` fails
with "Missing required positional argument".

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat(tts): add --help examples and fix required:false for --list

Add examples section to `tts --help` matching the pattern from other
commands (transcribe, render, etc.). Fix citty positional arg requiring
explicit `required: false` for --list to work standalone.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs: add CLI command checklist to CLAUDE.md

Ensure new commands always get --help examples in help.ts.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/cli/src/whisper/manager.ts

@@ -1,9 +1,8 @@
 import { execFileSync } from "node:child_process";
-import { existsSync, mkdirSync, createWriteStream, rmSync } from "node:fs";
+import { existsSync, mkdirSync, rmSync } from "node:fs";
 import { homedir, platform } from "node:os";
 import { join } from "node:path";
-import { get as httpsGet } from "node:https";
-import { pipeline } from "node:stream/promises";
+import { downloadFile } from "../utils/download.js";
 
 const MODELS_DIR = join(homedir(), ".cache", "hyperframes", "whisper", "models");
 const DEFAULT_MODEL = "small.en";
@@ -15,31 +14,6 @@ export interface WhisperResult {
   source: WhisperSource;
 }
 
-// --- Download helper --------------------------------------------------------
-
-function downloadFile(url: string, dest: string): Promise<void> {
-  return new Promise((resolve, reject) => {
-    const follow = (u: string) => {
-      httpsGet(u, (res) => {
-        if (res.statusCode === 301 || res.statusCode === 302) {
-          const location = res.headers.location;
-          if (location) {
-            follow(location);
-            return;
-          }
-        }
-        if (res.statusCode !== 200) {
-          reject(new Error(`Download failed: HTTP ${res.statusCode}`));
-          return;
-        }
-        const file = createWriteStream(dest);
-        pipeline(res, file).then(resolve).catch(reject);
-      }).on("error", reject);
-    };
-    follow(url);
-  });
-}
-
 function getModelUrl(model: string): string {
   return `https://huggingface.co/ggerganov/whisper.cpp/resolve/main/ggml-${model}.bin`;
 }