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-合并CLI超时核对.json

@@ -0,0 +1,17 @@
+{
+  "cliSucceeded": false,
+  "cliError": "Request timed out after 180000ms",
+  "underlyingResults": [
+    {
+      "path": "CodexOutput/upserver/KVGameplayLoopTests/fishing-fixed-runs/20260930T032500_c51bfd787cac474983d7863461e379e8/result.json",
+      "bytes": 954,
+      "sha256": "31377D6F60FF3D95B7AAC3779B2F5EA67CD3A2F7421874938865207AE6A5128A"
+    },
+    {
+      "path": "CodexOutput/upserver/KVGameplayLoopTests/reward-fixed-runs/20260930T032547_cae307d3ed07409a8a3c363c460357fa/result.json",
+      "bytes": 2375,
+      "sha256": "F2221B7A00DE5278948BABAEB0487C1E107BFDBB188CA135798666DEC422EC33"
+    }
+  ],
+  "followup": "Final individual CLI outputs are authoritative."
+}