Fail less often for intersection geometry

Especially when we use raw OSM footways, we break on so many intersection geometry cases (the circles):

I'll start looking into these, but I've also been looking at how https://github.com/StrandedKitty/streets-gl handles things. It's much more robust.

TODO:

- [ ] Can we have an optional mode where we don't trim back road center-lines at all and have empty intersection polygons, just to debug and see how it looks?
- [ ] Investigate what streets-gl does and see if we can adapt ideas from it

CC @BudgieInWA in case you're interested or have ideas. osm2streets has revived thanks to the Muv work. I'm kind of interested in getting footways and crossings all showing up exactly as they're in OSM, and generally getting rid of the old inferred sidewalks mode.

El issue trata sobre fallos en la geometría de intersecciones al procesar footways de OSM. Revisa el código de osm2streets que recorta las líneas centrales de las carreteras y crea polígonos de intersección. Compáralo con el repositorio streets-gl para obtener ideas sobre robustez. Empieza implementando un modo de depuración opcional que desactive el recorte para visualizar la geometría sin modificar.

Escrito por el modelo de indexación a partir del texto del issue.