roneymoon/CollabX ? reverse-engineered prompt

Build me a modern collaboration app called CollabX for teams and workspaces. I want people to be able to sign in, create or join a workspace, browse structured channels, send instant direct messages, and share files smoothly in conversations. Keep it clean and polished, with a simple sidebar for workspaces and channels, a main chat area, and an easy way to switch between DMs and group chats.

Make it feel fast and real time, with messages and file updates appearing instantly. Use a nice, professional UI that looks good on desktop and mobile, and make the app feel ready for a small team to actually use. If you need to look up current docs online, go ahead. Please wire up the main flows end to end, and if anything is unclear, choose the simplest sensible version that works well.