Function find_string_field 

fn find_string_field(value: &Value, key: &str, depth: u8) -> Option<String>

First string value under key in a pre-order walk. The walk is depth-capped at 6: the captured shape is flat and top-level, so a deeper field is treated as absent (surfaced by the caller’s parse-miss log, never guessed at). String content is never searched, so a result text quoting worktreePath: cannot aim the reap.