Sunlight Indicators (Planner + Race Day)

RaceCraft now adds route-based sunlight context to both Planner and Race Day views.

What it includes

• Sunrise, sunset, civil dawn, and civil dusk events computed from route coordinates
• Multi-day event generation for long races
• Checkpoint phase classification:
  • night
  • pre_dawn_twilight
  • day
  • post_dusk_twilight
• Planner summary card with timeline strip and phase-based recommendations
• Race Day live sunlight status and recommendation updates as actual times change

Backend notes

• Solar calculations are generated in /api/calculate
• Payload key: sunlight
• Includes timezone fallback behavior (UTC) and warning metadata when timezone resolution is unavailable

Frontend notes

• Shared helpers are implemented in static/js/sunlight.js
• Planner uses the payload for summary strip + checkpoint phase chips
• Race Day uses the same payload for live status text and timeline rendering