Add authors, messages & profile page

skillswap/package-lock.json

skillswap/package.json

skillswap/src/components/header.jsx

skillswap/src/components/ui/avatar.jsx

skillswap/src/components/ui/tabs.jsx

skillswap/src/components/ui/textarea.jsx

skillswap/src/index.css

skillswap/src/main.jsx

skillswap/src/pages/Authors.jsx

skillswap/src/pages/Messages.jsx

skillswap/src/pages/Profile.jsx