fix(sync): prevent master state from clearing when a peer pairs

When a device pairs with the master, the master's autopass can emit an update
and applyRemoteUpdate would sometimes apply an empty or weaker snapshot from the
merged view, overwriting the master's state. Skip applying remote state when
we're the master and the incoming snapshot has less content (servers + vhosts +
serviceTunnels) than current state.

native-host/managers/sync-manager.js

@@ -204,6 +204,13 @@ function onRemoteUpdate() {
   }, REMOTE_UPDATE_DEBOUNCE_MS);
 }
 
+function snapshotContentSize(snapshot) {
+  if (!snapshot || typeof snapshot !== 'object') return 0;
+  return (Array.isArray(snapshot.servers) ? snapshot.servers.length : 0) +
+    (Array.isArray(snapshot.virtualHosts) ? snapshot.virtualHosts.length : 0) +
+    (Array.isArray(snapshot.serviceTunnels) ? snapshot.serviceTunnels.length : 0);
+}
+
 async function applyRemoteUpdate() {
   if (weJustPushed || !pass || !holesailManager) return;
   try {
@@ -219,13 +226,20 @@ async function applyRemoteUpdate() {
       return;
     }
     const statePath = getStateFilePath();
+    let current = null;
     if (statePath && fs.existsSync(statePath)) {
       try {
         const currentRaw = fs.readFileSync(statePath, 'utf8');
-        const current = JSON.parse(currentRaw);
+        current = JSON.parse(currentRaw);
         if (stateFingerprint(current) === stateFingerprint(snapshot)) return;
       } catch (_) {}
     }
+    const identity = loadIdentity();
+    if (identity && identity.isMaster) {
+      const currentSize = current ? snapshotContentSize(current) : snapshotContentSize(holesailManager.getStateSnapshot());
+      const snapshotSize = snapshotContentSize(snapshot);
+      if (snapshotSize < currentSize) return;
+    }
     await applySyncedState(snapshot);
     lastSyncedAt = Date.now();
     if (emitEvent) emitEvent('syncApplied', {});