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。

CodexOutput/upserver/B3BatchMigration/M2/M2-C2d-fixture-regression.cs.txt

@@ -0,0 +1,7 @@
+if (UnityEditor.EditorApplication.isPlayingOrWillChangePlaymode) throw new System.InvalidOperationException("Idle Editor required");
+var results = new System.Collections.Generic.Dictionary<string,string>();
+foreach (var name in new[] { "fishing-consume", "fishing-reward" }) {
+    try { results[name] = await KVGameplayLoopSetup.RunValidationAsync(name); }
+    catch (System.Exception ex) { results[name] = "FAILED: " + ex.ToString(); }
+}
+return new { consumption = results["fishing-consume"], reward = results["fishing-reward"], state=KVGameplayLoopSetup.State() };