Replace the browser's robotic Web Speech API (espeak on Chromium) as the
primary read-aloud path with server-side Piper neural TTS, served by petal
and kept fully offline on millenia next to Ollama.
- internal/tts: proxy short passages to Piper, transcode WAV -> mp3/opus via
ffmpeg, content-addressed disk cache (instant re-taps). Each Piper instance
loads one voice, so language routes to its own endpoint:{voice}. Unknown
language -> 404 so the client falls back to Web Speech. UTF-8-safe truncation
for multibyte (Chinese) text.
- config: TTS_ENDPOINT / TTS_ENDPOINT_ZH / TTS_VOICE_EN / TTS_VOICE_ZH /
TTS_CACHE_DIR / TTS_TIMEOUT / TTS_AUDIO_FORMAT. Route mounts only when
TTS_ENDPOINT is set; otherwise unchanged behavior.
- web/audio/speech.ts: speak() hits /api/tts first, falls back to Web Speech on
any failure; rapid-tap-safe via a request token. Call sites unchanged.
- deploy/: Piper user systemd units (EN :5005, ZH :5006), setup script, README.
English (en_US-amy-medium) and Chinese (zh_CN-huayan-medium) are both live.
Claude-Session: https://claude.ai/code/session_016Yr6jELuRc7hyzYLccQKZd
5120b1e5a2