feat: show systemd service logs in service details (#2440)

Co-authored-by: hank <hank@henrygd.me>

internal/hub/transport/transport.go

@@ -115,6 +115,16 @@ func unmarshalLegacyResponse(resp common.AgentResponse, action common.WebSocketA
 		}
 		*d = resp.ServiceInfo
 		return nil
+	case common.GetSystemdLogs:
+		d, ok := dest.(*string)
+		if !ok {
+			return fmt.Errorf("unexpected dest type for GetSystemdLogs: %T", dest)
+		}
+		if resp.String == nil {
+			return errors.New("no systemd logs in response")
+		}
+		*d = *resp.String
+		return nil
 	}
 	return fmt.Errorf("unsupported action: %d", action)
 }

internal/hub/transport/transport_test.go

@@ -31,3 +31,12 @@ func TestUnmarshalSmartDataResponse(t *testing.T) {
 		})
 	}
 }
+
+func TestUnmarshalSystemdLogsResponse(t *testing.T) {
+	logs := "2026-09-27T12:00:00+00:00 host nginx[1]: started"
+	response := common.AgentResponse{String: &logs}
+
+	var result string
+	require.NoError(t, UnmarshalResponse(response, common.GetSystemdLogs, &result))
+	assert.Equal(t, logs, result)
+}