feat: save to remote can be authed by Kerberos

app.go

@@ -337,10 +337,20 @@ func (a *App) runSaveRemotePipeline(pngBytes []byte) error {
 	}
 	slog.Info("save-remote dispatch",
 		"host", cfg.SSH.Host, "user", cfg.SSH.User, "port", cfg.SSH.Port,
-		"png_size", len(pngBytes))
+		"auth_method", cfg.SSH.AuthMethod, "png_size", len(pngBytes))
+
+	// Select the uploader by auth method: Kerberos delegates to the system
+	// ssh/scp binaries (reusing the kinit credential cache), while builtin
+	// uses the in-process Go SSH client.
+	var uploader application.SSHUploader
+	if cfg.SSH.IsKerberos() {
+		uploader = sshpkg.NewKerberosUploader(cfg.SSH)
+	} else {
+		uploader = sshpkg.NewUploader(cfg.SSH)
+	}
 
 	svc := &application.CaptureAndSSHService{
-		Uploader:  sshpkg.NewUploader(cfg.SSH),
+		Uploader:  uploader,
 		Clipboard: a.clip,
 		Notifier:  &runtimeNotifier{ctx: a.ctx},
 		Cfg:       cfg.SSH,
@@ -446,7 +456,17 @@ func (a *App) TestConnection(cfg domain.S3Config) error {
 func (a *App) TestSSHConnection(cfg domain.SSHConfig) error {
 	slog.Info("RPC TestSSHConnection",
 		"host", cfg.Host, "user", cfg.User, "port", cfg.Port,
+		"auth_method", cfg.AuthMethod,
 		"strict_host_key", cfg.StrictHostKey, "has_password", cfg.Password != "")
+	// Kerberos auth delegates to the system ssh binary (see KerberosUploader)
+	// so its probe path differs from the in-process client.
+	if cfg.IsKerberos() {
+		if err := sshpkg.TestKerberosConnection(a.ctx, cfg); err != nil {
+			slog.Error("RPC TestSSHConnection (kerberos) failed", "err", err)
+			return err
+		}
+		return nil
+	}
 	if err := sshpkg.TestConnection(a.ctx, cfg); err != nil {
 		slog.Error("RPC TestSSHConnection failed", "err", err)
 		return err