[FEAT] Consider grenzüberschreitende Endstationen for fare calculation #200
Description
Is your feature request related to a problem? Please describe.
Currently, fare calculations seem to assume the last German station as the default destination. However, in some cases, tickets to the first station across the border (e.g., Saarbrücken → Saargemünd or Dresden → Děčín) are cheaper or equivalent, but the system does not automatically suggest this. This can frustrate users who are unaware of these potential savings.
Describe the solution you'd like
It would be helpful if the system could:
Recognize when a border station ticket might be cheaper than the last domestic station.
Suggest or allow users to select the first foreign station as an alternative destination in the fare calculation.
Describe alternatives you've considered
Users manually check neighboring foreign stations, but this is inconvenient and not obvious.
Documentation could suggest this trick, but integration into the pricing system would be more user-friendly.
Additional context
Examples where this occurs:
Saarbrücken → Saargemünd (France)
Dresden → Děčín (Czechia)
Trier → Luxembourg
This could improve transparency and help users find the best fare automatically.