feat(upserver): 保存M2客户端KV迁移至本人统计写检查点

保存独立KV用户服务、固定会话存档与原业务接线，以及C3d资料缓存和C3e本人统计写。
保留原PF/AGG路线、业务公式和时序；榜单读取、好友资料、公告、匹配及首场景闸仍待完成。

验证：ServiceHost两条件各33组646断言；Unity CLI Loop编译0错误269警告。
包含相关方案、评审裁决、测试及状态文档。未操作服务器、正式账号或打包。

Client/Assets/Scripts/Services/FootPrintService.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 public interface IFootPrintService
 {
     public EFootPrint FootPrint { get; }
@@ -11,6 +11,8 @@ public interface IFootPrintService
 // ReSharper disable once ClassNeverInstantiated.Global
 public class FootPrintService : IFootPrintService
 {
+        [asap.core.Inject] public game.PlayerDataStorage.IPlayerSaveStore SaveStore { get; set; }
+
     private EFootPrint _footPrint;
     private ulong _kvCompleteFootPrint;
     internal ulong CompleteFootPrintForKVValidation => _kvCompleteFootPrint;
@@ -39,13 +41,15 @@ public class FootPrintService : IFootPrintService
 
     public void UploadData()
     {
-        var data = (ulong)_footPrint;
-        PlayFabMgr.Instance.UpdateUserDataValue("FootPrint", data.ToString());
+        _kvCompleteFootPrint |= unchecked((uint)(int)_footPrint);
+        var data = _kvCompleteFootPrint;
+        SaveStore.Write("FootPrint", data.ToString()).RequireAccepted();
     }
 
     public void LoadData(string data)
     {
-        _footPrint = (EFootPrint) ulong.Parse(data);
+        _kvCompleteFootPrint = ulong.Parse(data);
+        _footPrint = unchecked((EFootPrint)(int)(uint)_kvCompleteFootPrint);
     }
 
     public bool HasFootPrint(EFootPrint state)