- speakText: revert async ElevenLabs fetch chain — browser requires
speechSynthesis.speak() to be called synchronously within user gesture;
async .catch() context caused silent failure across browsers
- copyText: fix fallback that always showed 'Copied!' even when it failed;
now shows real error message, uses selectNodeContents for accuracy,
handles missing clipboard API gracefully
- Switch speakText() to call /api/text-to-speech backend (ElevenLabs) with fallback to native speechSynthesis
- Upgrade ElevenLabs voice from Rachel to Adam (pNInz6obpgDQGcFmaJgB) — warmer, more professional
- Upgrade model from eleven_monolingual_v1 to eleven_turbo_v2_5 for better quality and lower latency
