v1.2.1

Changelog:

• Furigana readings: speak the reading instead of base text for correct pronunciation of proper nouns/rare readings (toggle, default on).
• Voice tuning: added pitch, intonation, volume, and pause-length controls alongside speed.
• Voice picker: new UI to browse voices with icons + preview clips; voices are playback.
• Fix: stale synthesis no longer plays over a newer utterance.