v2.0.1 Brodcast delay extended & auto download configurable

Improvements

• Broadcast delay up to 5 minutes — Live Timing Offset slider now extends to -5m (previously -60s) to accommodate longer streaming-service lag, with M:SS formatting and ±30s quick-adjust buttons
• Configurable auto-precompute — new AUTO_PRECOMPUTE env var controls which session types the background task fetches during race weekends. Accepts off, race, race+qual (default), or all. Self-hosters who don't watch practice can avoid downloading FP1/FP2/FP3 data; sessions outside the configured set are still available on-demand