- Hide voice-debug tab in production (href: null)
- Revert VoiceContext to stable version (no Samantha voice)
- Add platform badge to Debug screen (iOS/Android indicator)
- Remove PRD.md (moved to Ralphy workflow)
TTS voice quality improvements caused 'speak function failed' error
on iOS Simulator (Samantha voice unavailable). Reverted to working
baseline: rate 0.9, pitch 1.0, default system voice.