feat(sync): default auto-sync interval to 120s

Raise the default autoSyncDebounceSeconds from 60 to 120. Update the ConfigCoreService getter fallback to match the vxcore ctor default and bump the vxcore submodule pointer to the corresponding change.

Author: tamlok

libs/vxcore

@@ -196,7 +196,7 @@ bool ConfigCoreService::setRecoverLastSessionEnabled(bool p_enabled) {
 
 int ConfigCoreService::getAutoSyncDebounceSeconds() const {
   QJsonObject config = getConfig();
-  int value = config.value(QStringLiteral("autoSyncDebounceSeconds")).toInt(60);
+  int value = config.value(QStringLiteral("autoSyncDebounceSeconds")).toInt(120);
   // Clamp to valid range
   if (value < c_minAutoSyncDebounceSeconds) {
     value = c_minAutoSyncDebounceSeconds;