The Quest Begins (The "Why") I still remember the first time I tried to add login to a side‑project. I’d read a tutorial that said “just store a token in localStorage and you’re good,” slapped together a few fetch calls, and called it a day. A week later I got an email from a user: “Hey, I can’t log out, and someone else seems to be using my account.” My heart sank. I realized I’d bolted a flashy lock onto a screen door — it looked secure, but anyone with a screwdriver could walk right in. ...