fix(opcuaclient): upstream session loss goes Bad and recovers (#670)

A bad keep-alive now degrades health (LastSuccessfulRead preserved) and,
once per outage, publishes BadNoCommunication (value retained) for every
subscribed ref plus a quality-only annotation on subscribed alarm
conditions. Good keep-alives and data/event notifications advance
LastSuccessfulRead, so an idle-but-alive subscription never looks dead
to the #527 watchdog. A keep-alive that recovers on the same session
re-reads the Bad refs and republishes them Good; a session that does not
come back is recovered by the watchdog's ShutdownAsync + InitializeAsync
+ re-subscribe.

Deletes the SessionReconnectHandler wiring (it retried forever in SDK
1.5.378, cloned subscriptions the driver never re-tracked and kept health
Healthy), OnReconnectComplete, TryRearmReconnect and the reconnect_*
counters (new keepalive_recovered). Teardown of a lost session skips
wire deletes and bounds CloseSession. SDK warnings reach the driver log.
Wire test reworked: restart => Bad, then watchdog-style reinit => Good.

docs/DriverLifecycle.md

@@ -422,7 +422,10 @@ Two consequences worth knowing:
 - **`CalculationDriver` can never trip it, correctly.** It reports `Healthy` whenever it is running and has
   no transport to be degraded about. Every other driver reaches a non-Healthy state on sustained failure:
   the nine poll drivers via `Degraded`, MQTT via its live connection state, Galaxy via its reconnect
-  supervisor. This was surveyed across all 12 before relying on it — it is the assumption the whole
+  supervisor, OpcUaClient via a bad session keep-alive (`Degraded`, since Gitea #670 — before that its health
+  only moved on `ReadAsync`, which a subscription-only driver never calls, so it stayed `Healthy` through any
+  outage and this survey was wrong about it; good keep-alives and notifications now advance its read stamp, so
+  an idle-but-alive subscription does not look dead either). This was surveyed across all 12 before relying on it — it is the assumption the whole
   mechanism rests on.
 - **A device that accepts a connection but serves no data will cycle**, reconnecting once per threshold.
   That is the correct reading of a broken device, it is rate-limited, and it is visible in the health