A production-shaped messaging app built to serve as a reusable base for client "Live Chat" add-on work. Messages, edits, deletions, typing, and read receipts all stream live with zero polling. Optimistic sends show messages instantly, then reconcile with the server with no flicker. Read receipts update the moment the other person opens the chat. Message search jumps straight to matches and highlights them. Typing indicators and presence update in real time. Cursor-based infinite scroll handles hundreds of messages with no skips or duplicates. Every read and write is authorized server-side, rea