Fix date-fns panic errors in timeline and session metadata

• Prevents invalid time value errors when displaying dates
• Improves reliability of date parsing and formatting

Optimize transcript word rendering and scrolling performance

• Faster rendering of transcript words during active transcription
• Smoother scrolling experience in transcript view

Improve audio visualizer amplitude computation

• Better perceived loudness using RMS (Root Mean Square) instead of peak detection
• Logarithmic scaling that matches human hearing perception
• Smoother animations with reduced jitter
• Noise gate to hide background noise floor

Websocket connection timeout tuning