Function forked_title 

pub fn forked_title(title: &str) -> String

Freeze getForkedTitle (session.ts): /^(.+) \(fork #(\d+)\)$/ → base (fork #(n+1)), otherwise title (fork #1). Ported with string ops (regex .+ needs ≥1 char before the suffix → idx > 0, greedy match → last occurrence → rfind).