AuraFlow - Audio engine test

Focus, Relax, Sleep, and Move with real-time generated stereo audio. * Smooth crossfades, layer mixing, intensity, palettes, and timers. * Animated visuals, time-aware adjustments, session history, and ratings. Audio-engine tests and the production build passed. Real-device listening and browser testing remain. This is the first web MVP. GPT-6 Astra integration, wearable biometrics, and native apps are still ahead.