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

pkg/models/client.go

@@ -4,6 +4,8 @@ import "github.com/gorilla/websocket"
 
 // Represents a GoTomato client
 type GoTomatoClient struct {
-	Conn     *websocket.Conn // The websocket connection of the client
+	Server   string          // The GoTomato server
 	Password string          // Pomodoro password
+	Conn     *websocket.Conn // The websocket connection of the client
+	LastErr  error           // Last client error
 }