feat: Implement initial client application with TUI for SSH tunnel management and monitoring.

cmd/client/main.go

@@ -35,6 +35,7 @@ func main() {
 	localPort := flag.String("local", "8080", "Local port to expose")
 	serverAddrFlag := flag.String("server", "", "Grokway server address")
 	tokenFlag := flag.String("token", "", "Authentication token (overrides config)")
+	hostHeaderFlag := flag.String("host-header", "", "Custom Host header to send to local service")
 	flag.Parse()
 
 	// Load config
@@ -56,7 +57,7 @@ func main() {
 		serverAddr = "localhost:2222"
 	}
 
-	m := tui.InitialModel(*localPort, serverAddr, authToken)
+	m := tui.InitialModel(*localPort, serverAddr, authToken, *hostHeaderFlag)
 	p := tea.NewProgram(m, tea.WithAltScreen())
 
 	if _, err := p.Run(); err != nil {