Add advanced sync logging for debugging host-client sync issues

- Add LogSync() helper method in Main.cs for consistent sync logging
- Log all packet send/receive events in PacketHandler and Packet classes
- Add detailed building placement logging in WorldPlace.cs (all properties, final state)
- Add building state update logging in BuildingStatePacket.cs
- Add building state send logging in BuildingStateManager.cs

All sync logs are prefixed with [SYNC] for easy filtering.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Packets/State/BuildingStatePacket.cs

@@ -58,6 +58,14 @@ namespace KCM.Packets.State
             if (building == null)
                 return;
 
+            Main.LogSync($"========== BUILDING STATE UPDATE ==========");
+            Main.LogSync($"Building: {uniqueName} guid={guid}");
+            Main.LogSync($"  globalPosition={globalPosition}");
+            Main.LogSync($"  localPosition={localPosition}");
+            Main.LogSync($"  rotation={rotation} (euler={rotation.eulerAngles})");
+            Main.LogSync($"  built={built}, placed={placed}, open={open}");
+            Main.LogSync($"  constructionProgress={constructionProgress}");
+
             try
             {
                 building.UniqueName = uniqueName;