fix(management): purge terminal PendingSecuredWrites rows on the list sweep after a retention window (review 2026-10-21 08/G3)

src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementServiceOptions.cs

@@ -10,4 +10,10 @@ public class ManagementServiceOptions
 
     /// <summary>Age after which a Pending secured write can no longer be approved; it is transitioned to Expired at the next decision/list touch. Default 24 hours. A non-positive value disables server-side expiry.</summary>
     public TimeSpan SecuredWritePendingTtl { get; set; } = TimeSpan.FromHours(24);
+
+    /// <summary>Age after which a decided/executed secured-write row (Approved/Rejected/Expired/Executed/Failed, measured from its last lifecycle instant) is purged from <c>PendingSecuredWrites</c>; the AuditLog keeps the history. Default 90 days. A non-positive value disables the purge.</summary>
+    public TimeSpan SecuredWriteTerminalRetention { get; set; } = TimeSpan.FromDays(90);
+
+    /// <summary>Minimum interval between terminal secured-write purge passes on one node (the purge rides the Secured Writes list sweep). Default 1 hour; zero runs it on every list.</summary>
+    public TimeSpan SecuredWriteTerminalPurgeInterval { get; set; } = TimeSpan.FromHours(1);
 }