fix(models): surface DeviceError's name attribute, not just its message

ErrorsResponse.Error() only returned the <error> element's text body,
dropping the name attribute entirely. Some speaker error responses
have a Message that just restates Value as text (e.g. a bare "1047"
for SOURCE_ALREADY_REMOVED), so callers only ever saw the useless
numeric string. Found while live-debugging a Deezer account
add/remove cycle on real hardware, where the raw XML
(<error value="1047" name="SOURCE_ALREADY_REMOVED">1047</error>)
carried real information only in the name attribute.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

pkg/models/device.go

@@ -2,6 +2,8 @@ package models
 
 import (
 	"encoding/xml"
+	"fmt"
+	"strconv"
 	"time"
 )
 
@@ -80,7 +82,7 @@ type ErrorsResponse struct {
 // Error implements the error interface for ErrorsResponse
 func (e *ErrorsResponse) Error() string {
 	if len(e.Errors) > 0 {
-		return e.Errors[0].Message
+		return e.Errors[0].Error()
 	}
 
 	return "unknown API error"
@@ -93,6 +95,27 @@ type DeviceError struct {
 	Message string `xml:",chardata"`
 }
 
+// Error implements the error interface for DeviceError. Some speakers
+// return a Message that just restates Value as text (e.g. a bare "1047"
+// for an error the firmware has no localized string for) — Name is the
+// only informative part in that case, so it's always included unless
+// Message already carries it.
+func (e DeviceError) Error() string {
+	if e.Name == "" {
+		if e.Message == "" {
+			return fmt.Sprintf("device error %d", e.Value)
+		}
+
+		return e.Message
+	}
+
+	if e.Message == "" || e.Message == e.Name || e.Message == strconv.Itoa(e.Value) {
+		return fmt.Sprintf("%s (%d)", e.Name, e.Value)
+	}
+
+	return fmt.Sprintf("%s: %s", e.Name, e.Message)
+}
+
 // DiscoveredDevice represents a device found through network discovery
 type DiscoveredDevice struct {
 	Name            string    `json:"name"`

pkg/models/device_error_test.go

@@ -0,0 +1,69 @@
+package models
+
+import "testing"
+
+func TestDeviceError_Error(t *testing.T) {
+	tests := []struct {
+		name     string
+		err      DeviceError
+		expected string
+	}{
+		{
+			name:     "message repeats the numeric value (real speaker case)",
+			err:      DeviceError{Value: 1047, Name: "SOURCE_ALREADY_REMOVED", Message: "1047"},
+			expected: "SOURCE_ALREADY_REMOVED (1047)",
+		},
+		{
+			name:     "message is empty",
+			err:      DeviceError{Value: 1047, Name: "SOURCE_ALREADY_REMOVED", Message: ""},
+			expected: "SOURCE_ALREADY_REMOVED (1047)",
+		},
+		{
+			name:     "message is meaningful and distinct from name",
+			err:      DeviceError{Value: 1029, Name: "UNKNOWN_ACTION_ERROR", Message: "This version of SCM does not support spotify create account functionality."},
+			expected: "UNKNOWN_ACTION_ERROR: This version of SCM does not support spotify create account functionality.",
+		},
+		{
+			name:     "name is empty, message carries the detail",
+			err:      DeviceError{Value: 500, Name: "", Message: "internal error"},
+			expected: "internal error",
+		},
+		{
+			name:     "both name and message are empty",
+			err:      DeviceError{Value: 500, Name: "", Message: ""},
+			expected: "device error 500",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.err.Error(); got != tt.expected {
+				t.Errorf("expected %q, got %q", tt.expected, got)
+			}
+		})
+	}
+}
+
+func TestErrorsResponse_Error(t *testing.T) {
+	t.Run("delegates to the first DeviceError", func(t *testing.T) {
+		errs := &ErrorsResponse{
+			Errors: []DeviceError{
+				{Value: 1047, Name: "SOURCE_ALREADY_REMOVED", Message: "1047"},
+			},
+		}
+
+		expected := "SOURCE_ALREADY_REMOVED (1047)"
+		if got := errs.Error(); got != expected {
+			t.Errorf("expected %q, got %q", expected, got)
+		}
+	})
+
+	t.Run("no errors", func(t *testing.T) {
+		errs := &ErrorsResponse{}
+
+		expected := "unknown API error"
+		if got := errs.Error(); got != expected {
+			t.Errorf("expected %q, got %q", expected, got)
+		}
+	})
+}