merge: Mqtt runtime + Transport code review — deaf-reconnect subscription reset (High), teardown-before-reinit session leak (High), timeout normalization, dead CA-pin warning; 12 findings

docs/drivers/Mqtt.md

@@ -404,6 +404,17 @@ nothing forever, so `OnReconnectedAsync` **throws** when zero filters are grante
 down rather than swallowing it. A SUBACK failure degrades just the affected RawPaths to
 `BadCommunicationError`.
 
+There are **two** kinds of reconnect and only one of them fires that callback. A drop the connection's
+own supervisor recovers keeps the same `MqttConnection`, so `Reconnected` → `OnReconnectedAsync`
+re-establishes every live filter. A **session rebuild** — `ShutdownAsync` + `InitializeAsync` (the #527
+comms-loss watchdog's retry path, and an `ApplyDelta` that changes the endpoint or credentials) — builds
+a *new* connection and re-attaches the *same* `MqttSubscriptionManager`, and the re-subscribe then comes
+from the host (`DriverInstanceActor.ResubscribeDesired`) rather than from the callback. `AttachTo`
+therefore **forgets the filters the previous session had established**: the dedupe set is a claim about
+one session, and carrying it across made the host's re-subscribe resolve an empty pending set, send no
+SUBSCRIBE at all, and leave the driver Connected/Healthy and permanently deaf. Sparkplug's
+`SparkplugIngestor.AttachTo` resets its own session state for the same reason.
+
 ## Write-through
 
 `IWritable` landed with [#508](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/508). Before it,