Route comparison: Optionally show walking / cycling route alongside car

See v1 for comparison.

Basically, when checking out routing impact - we currently only draw a route-line for a car trip.

We could also add a pedestrian and cycling trip, typically showing that they are not negatively impacted. In fact they may now be along a much quieter street.

Look for the routing and map drawing code, likely in modules handling trip simulation and UI rendering. Start by finding where the car route line is currently drawn. Investigate the routing engine to see if pedestrian and cycling trips can be calculated and visualized alongside. Check for existing tests related to routing or map display to understand the expected behavior.

Written by the indexing model from the issue text.