Customize flight trail colors based on altitude

[Splestule]

Goal

Make flight trails display different colors based on the aircraft's altitude, creating a more informative visualization.

Background

Currently, flight trails are a single color. Color-coding by altitude would help users quickly identify high-altitude vs. low-altitude flights and make the visualization more engaging.

What needs to be done

1. Create a color gradient function based on altitude
2. Modify FlightTrajectory component to use altitude-based colors
3. Consider adding a legend or indicator

Relevant files

• client/src/components/FlightTrajectory.tsx - Trail rendering component

Suggested color scheme

Altitude	Color	Hex
< 3,000 ft (landing/takeoff)	Green	#22c55e
3,000 - 15,000 ft (climbing/descending)	Yellow	#eab308
15,000 - 30,000 ft (mid-altitude)	Orange	#f97316
> 30,000 ft (cruising)	Red	#ef4444

Acceptance criteria

• Trail colors change based on altitude
• Color transitions are smooth (optional: gradient along trail)
• Colors are visible against the map/terrain
• Works in both 3D map and VR modes