The Quest Begins (The “Why”) I still remember the first day I opened the legacy repo at my last job. The README was a single line: “Good luck.” Inside, a 5‑kiloline monster lived—a mix of PHP, JavaScript, and a sprinkle of bash that seemed to have been written during a caffeine‑fueled all‑nighter. Every time I tried to add a tiny feature, I felt like I was stepping on a landmine. Change one line, and somewhere else a silent bug would pop up, usually in a place I hadn’t touched in weeks. ...