v0.3.0

🎙️ v0.3.0 — OpenAI TTS + pluggable speech-to-text

• OpenAI text-to-speech — route speech through OpenAI's /v1/audio/speech under Settings → Voice → TTS Provider → OpenAI, with promptable voice instructions, adjustable speed, and a Test Voice preview (works for every provider). Contributed by @canyugs (#3).
• Pluggable speech-to-text — pick your transcription provider under Settings → Speech Input: Apple on-device (default) or cloud Whisper via Groq, OpenAI, or any OpenAI-compatible endpoint. Contributed by @canyugs (#4).
• Docs + zh-Hant localization for the new settings, plus a note clarifying cloud vs on-device voice privacy.

Full changelog: v0.2.1...v0.3.0