fix(mqtt): stale observed refs BadNoCommunication on connection loss so the identical replay recovers (05/STAB-18 shape a)

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Mqtt/MqttSubscriptionManager.cs

@@ -96,6 +96,9 @@ public sealed class MqttSubscriptionManager
     /// </summary>
     private const uint StatusBadWaitingForInitialData = 0x80320000u;
 
+    /// <summary>The broker session this driver was observing is gone — see <see cref="OnConnectionLost"/>.</summary>
+    private const uint StatusBadNoCommunication = 0x80310000u;
+
     private readonly int _defaultQos;
     private readonly string _driverId;
     private readonly ILogger? _logger;
@@ -237,6 +240,45 @@ public sealed class MqttSubscriptionManager
         _transport = connection;
         connection.MessageReceived += HandleMessage;
         connection.Reconnected += OnReconnectedAsync;
+        connection.ConnectionLost += OnConnectionLost;
+    }
+
+    /// <summary>
+    ///     Marks every already-observed reference <c>BadNoCommunication</c>, <b>keeping its last
+    ///     value</b>, and publishes the change — the driver's answer to a lost broker session
+    ///     (archreview 05/STAB-18 shape a). Wired to <see cref="MqttConnection.ConnectionLost"/> by
+    ///     <see cref="AttachTo"/>; public so tests (and Sparkplug's ingestor) can drive the edge
+    ///     directly.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         <b>This is what makes the reconnect recover.</b> The steady-state suppression in
+    ///         <see cref="Deliver"/> compares value AND status against the driver-owned cache, which
+    ///         survives reconnects and redeploys — so the retained replay of an unchanged payload was
+    ///         suppressed and every node latched Bad by the host stayed Bad until the plant value
+    ///         happened to change. Staling the status first makes that identical replay a change.
+    ///     </para>
+    ///     <para>
+    ///         A never-observed reference is left alone (it is already
+    ///         <see cref="StatusBadWaitingForInitialData"/>, which says something more precise), and an
+    ///         already-Bad one is not re-stamped. Runs on MQTTnet's dispatcher thread: dictionary work
+    ///         and synchronous <see cref="OnDataChange"/> invokes only — exactly what
+    ///         <see cref="Deliver"/> already does there — and never awaits.
+    ///     </para>
+    /// </remarks>
+    public void OnConnectionLost()
+    {
+        var now = DateTime.UtcNow;
+        foreach (var rawPath in _authored.ByRawPath.Keys)
+        {
+            var prior = Values.Read(rawPath);
+            if (prior.StatusCode == StatusBadWaitingForInitialData) continue;   // never observed
+            if ((prior.StatusCode >> 30) >= 2) continue;                        // already Bad
+
+            var staled = prior with { StatusCode = StatusBadNoCommunication, ServerTimestampUtc = now };
+            Values.Update(rawPath, staled);
+            Raise(rawPath, staled);
+        }
     }
 
     /// <summary>