Support attaching existing Restic repositories

internal/restic/restic.go

@@ -414,7 +414,7 @@ func resticError(message string, commandErr error) error {
 	case strings.Contains(lower, "wrong password") || strings.Contains(lower, "no key found"):
 		return errors.New("authentication: wrong repository password. Enter the original Restic password under Edit and select Test")
 	case strings.Contains(lower, "repository does not exist") || strings.Contains(lower, "is there a repository at the following location?"):
-		return errors.New("repository: destination is not initialized; open Repositories and select Initialize once")
+		return errors.New("repository: Am konfigurierten Ziel wurde keine Restic-config gefunden. Für ein vorhandenes Repository den exakten Repository-Ordner eintragen; nur ein wirklich neues, leeres Ziel initialisieren")
 	default:
 		message = strings.TrimSpace(strings.TrimPrefix(message, "Fatal:"))
 		return fmt.Errorf("restic: %s: %w", message, commandErr)

internal/restic/restic_test.go

@@ -298,6 +298,13 @@ func TestResticErrorExplainsCiphertextVerification(t *testing.T) {
 	}
 }
 
+func TestResticErrorExplainsMissingExistingRepositoryPath(t *testing.T) {
+	err := resticError("Fatal: repository does not exist", fmt.Errorf("exit status 10"))
+	if !strings.Contains(err.Error(), "exakten Repository-Ordner") || !strings.Contains(err.Error(), "wirklich neues") {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
 func TestRunnerPausesResumesAndCancelsProcessGroup(t *testing.T) {
 	dir := t.TempDir()
 	ticksPath := filepath.Join(dir, "ticks")