feat(management): server-side secured-write TTL — stale pending writes expire, never execute (arch-review S2)

Claude-Session: https://claude.ai/code/session_01MtdgwpEeCUn6cUA5f1LMPj

src/ZB.MOM.WW.ScadaBridge.Commons/Types/Enums/AuditKind.cs

@@ -24,6 +24,14 @@ public enum AuditKind
     SecuredWriteReject,
     SecuredWriteExecute,
 
+    /// <summary>
+    /// A Pending secured write aged past its server-side TTL and was transitioned to
+    /// <c>Expired</c> without ever executing — the stale setpoint is never relayed to
+    /// the site. Emitted best-effort by the system (no verifier) when the approve/reject
+    /// path or the opportunistic list sweep observes an overdue Pending row. (arch-review S2)
+    /// </summary>
+    SecuredWriteExpire,
+
     /// <summary>
     /// A reconciliation pull row that failed to insert on every retry up to the
     /// permanent-abandon threshold, so central advanced its cursor past it and