perf: async autosave for dedicated server

Autosave previously froze the main thread for 2-6 seconds while
compressing the entire save file with zlib. Now the save buffer is
snapshotted under the lock (~18ms), then compression runs on a
background thread. The compressed data is committed to StorageManager
on the next main-thread tick via CommitPendingAsyncSave().

Also skip redundant full chunk saves during autosave on the dedicated
server -- chunks are already persisted by the per-tick trickle save.
Only entity data is flushed, matching Xbox/Orbis behavior.

Added per-step timing to the autosave handler for diagnostics.

Minecraft.Server/Windows64/ServerMain.cpp

@@ -16,6 +16,7 @@
 #include "..\Security\IdentityTokenManager.h"
 #include "..\WorldManager.h"
 #include "..\Console\ServerCli.h"
+#include "..\..\Minecraft.World\ConsoleSaveFileOriginal.h"
 #include "Tesselator.h"
 #include "Windows64/4JLibs/inc/4J_Render.h"
 #include "Windows64/GameConfig/Minecraft.spa.h"
@@ -330,6 +331,7 @@ static void TickCoreSystems()
 	g_NetworkManager.DoWork();
 	ProfileManager.Tick();
 	StorageManager.Tick();
+	ConsoleSaveFileOriginal::CommitPendingAsyncSave();
 }
 
 /**