Function run_fix 

pub fn run_fix(
    scan_path: &Path,
    cfg: &Config,
    today: NaiveDate,
) -> Result<FixSummary>

Core logic for timebomb defuse.

Pass 1 — interactive: scan for detonated fuses and prompt the user for each one.

Pass 2 — apply: group decisions by file, sort line numbers descending, and apply edits bottom-up so earlier line numbers are not shifted by removals.

Always returns Ok(FixSummary); the caller exits 0.