feat: reconnect on disconnect (add status to TUI)

- add `Connected()` method for client
- add `LastErr` field to GoTomatoClient
  - replace error logging by updating `LastErr` field
  - modify methods to use pointer receivers for Client
- add `prevMessage` variable to store the last received server message
- show connect status in TUI
- use EnterAltScreen instead of ClearScreen

cmd/client/app.go

@@ -49,10 +49,14 @@ func (a app) waitForChannelSignal() tea.Cmd {
 func (a app) Init() tea.Cmd {
 	client = websocket.Connect(config.URL)
 	client.Password = config.Password
+	if client.LastErr != nil {
+		helper.Logger.Fatal(client.LastErr)
+	}
+
 	go client.ProcessServerMessages(a.channel)
 
 	return tea.Batch(
-		tea.ClearScreen,
+		tea.EnterAltScreen,
 		a.waitForChannelSignal(),
 	)
 }