A Friday night scuffle on a Monterrey city bus turned deadly. By Monday, a judge had the passenger in preventive custody, and prosecutors pushed a lesser-intent homicide theory built for fights that go too far. The driver—well known to riders—collapsed after the argument and later died. Now the hearing is set to resume Friday with video, forensics, and a legal term most people don’t hear every day: preterintentional homicide. What that means —and…