Samarkand can be solved trivially by self-apply

Hi,
I was trying out the game and it was really fun! But on level 8 I was a bit stumped as there was no hint and I saw that the goal theorem preimage_injective is available and tried applying it and it just worked? I am a little confused as to why that was allowed

Thanks. This is indeed a known big that needs to be fixed in lean4game.

I'd be happy to try and figure out how to make a bugfix :) will try to spend some time next week on it