Can I vibecode ElevenLabs?

Build me a personal text-to-speech workbench, the DIY slice of ElevenLabs.
Requirements:

- A Node CLI plus a small local web page (Express, localhost only): paste text,
  pick a voice preset, get an mp3.
- Engine 1: Piper or Kokoro running locally on CPU, free and private. Engine 2:
  optional OpenAI TTS fallback, key in .env, for when quality beats privacy.
- Save every generation to ~/TTS/YYYY-MM-DD/<slug>.mp3 with a sidecar .txt
  holding the input text plus the engine and voice used.
- Voice presets in voices.json: name, engine, voice id, speed.
- Batch mode: point it at a folder of .txt files, get a folder of mp3s, for
  narrating notes or articles.
- No accounts, no telemetry, local-first; the only network calls are the
  optional hosted API.
- Out of scope: voice cloning, dubbing, and emotional voice direction. Never
  clone a real person's voice; that is exactly the part that should not be DIY.
- README: model download steps, and state honestly that the voice quality gap
  versus ElevenLabs is real; frontier voice models plus licensing are the
  product and cannot be rebuilt solo.