Application state and event handling - How the App struct in src/app.rs holds UI state, routes AppEvent values, handles keys, ingests messages and runs background tasks.
Runtime and event loop - Process startup in src/main.rs, the tokio runtime, the two event channels, the input thread, the WhatsApp forwarder and the draw/recv TUI loop.
Terminal UI rendering - How src/ui.rs draws the connecting, QR pairing and main screens with ratatui, including message formatting, wrapping, the input box and the footer.
