[client] UI refactor (#6069)

Refactor UI

---------

Co-authored-by: Eduard Gert <kontakt@eduardgert.de>
Co-authored-by: braginini <bangvalo@gmail.com>
Co-authored-by: Pascal Fischer <32096965+pascal-fischer@users.noreply.github.com>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: riccardom <riccardomanfrin@gmail.com>

client/ui/services/errors_test.go

@@ -0,0 +1,50 @@
+//go:build !android && !ios && !freebsd && !js
+
+package services
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	gcodes "google.golang.org/grpc/codes"
+	gstatus "google.golang.org/grpc/status"
+)
+
+func TestErrorClassifier_Classify(t *testing.T) {
+	c := errorClassifier{} // nil translator → Short is the bare "error.<code>" key
+
+	t.Run("permission denied by gRPC code with a clean desc", func(t *testing.T) {
+		// The daemon now forwards the innermost status: code + clean desc that
+		// no longer carries the English "permission denied" marker.
+		err := gstatus.Error(gcodes.PermissionDenied, "peer is already registered by a different User or a Setup Key")
+
+		ce := c.classify(err)
+		require.NotNil(t, ce)
+		require.Equal(t, "permission_denied", ce.Code)
+		require.Equal(t, "error.permission_denied", ce.Short)
+		require.Equal(t, "peer is already registered by a different User or a Setup Key", ce.Long)
+	})
+
+	t.Run("substring match still wins for unclassified codes", func(t *testing.T) {
+		err := gstatus.Error(gcodes.Unknown, "peer login has expired")
+
+		ce := c.classify(err)
+		require.NotNil(t, ce)
+		require.Equal(t, "session_expired", ce.Code)
+	})
+
+	t.Run("unavailable code maps to daemon_unreachable", func(t *testing.T) {
+		ce := c.classify(gstatus.Error(gcodes.Unavailable, "transport closing"))
+		require.Equal(t, "daemon_unreachable", ce.Code)
+	})
+
+	t.Run("unmatched stays unknown", func(t *testing.T) {
+		ce := c.classify(errors.New("something odd"))
+		require.Equal(t, "unknown", ce.Code)
+	})
+
+	t.Run("nil error", func(t *testing.T) {
+		require.Nil(t, c.classify(nil))
+	})
+}