feat: backup the original file before manage it by lazyssh (#49)

internal/adapters/data/ssh_config_file/config_io.go

@@ -66,6 +66,11 @@ func (r *Repository) saveConfig(cfg *ssh_config.Config) error {
 		return fmt.Errorf("failed to write config to temporary file: %w", err)
 	}
 
+	// Ensure a one-time original backup exists before any modifications managed by lazyssh.
+	if err := r.createOriginalBackupIfNeeded(); err != nil {
+		return fmt.Errorf("failed to create original backup: %w", err)
+	}
+
 	if err := r.createBackup(); err != nil {
 		return fmt.Errorf("failed to create backup: %w", err)
 	}