Day 91 of #100DaysOfCode — DevCollab: Next.js Setup and Authentication

Today, the frontend starts. Day 91 was the most infrastructure-heavy day on the Next.js side, not because of what's visible, but because of what everything else depends on. The Axios instance with JWT interceptors, the auth context, protected routes, and the login and register pages. By the end of today, a user can register in the browser, be redirected to a dashboard, log out, log back in, and have the access token refreshed invisibly in the background when it expires. Setting Up the Next.js Pr