feat: use bubbletea framework

- implement TUI in bubbletea
  - split components into separate files
- remove now unused functions
- restructure files

internal/helper/files.go

@@ -10,7 +10,7 @@ import (
 	ChronoTomato "git.smsvc.net/pomodoro/ChronoTomato/pkg/models"
 )
 
-// Expands the `~` in a passed filename
+// Expands the "~" in a passed filename
 func expandUnixPath(filename string) string {
 	if strings.HasPrefix(filename, "~/") {
 		dirname, _ := os.UserHomeDir()