test(otopcua): tighten multi-device collapse assertion + clear warn-state on removal (follow-up E)

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DriverHostActor.cs

@@ -770,6 +770,12 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
         // Map each matched device's subset under its equipment. ONE device per partition ⇒ the mapper collapses
         // that partition's single host folder ⇒ clean EQ-n/FOCAS/...; a plan with zero new variables (all
         // shadowed by authored refs) contributes no entry.
+        // NOTE: DiscoveredNodeMapper.Map's collapse predicate compares the host segment with RAW
+        // StringComparer.Ordinal, whereas we grouped on the NORMALIZED host. Harmless: a real FOCAS device
+        // emits one consistent HostAddress string per device, so a partition is single-host either way (collapse
+        // fires). Even if two raw spellings of the same host slipped into one partition, the only effect would be
+        // a retained (non-collapsed) host folder — never a mis-graft or NodeId collision (the equipment scope
+        // already isolates them).
         var plans = new Dictionary<string, DiscoveredInjectionPlan>(StringComparer.Ordinal);
         foreach (var (host, nodes) in matchedNodes)
         {
@@ -1534,6 +1540,9 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
             if (plansByEquipment.Count == 0)
             {
                 _discoveredByDriver.Remove(driverId);
+                // Drop the driver's partition warn-signature too so a permanently-removed/rebound driver doesn't
+                // leak a stale entry (log-level-only state; bounded by driver count — just tidiness).
+                _lastPartitionWarnSignature.Remove(driverId);
                 // FALLBACK (one-send invariant): this driver was SKIPPED in the bulk loop (it was cached), and its
                 // plan is now FULLY DROPPED — so ApplyDiscoveredPlansForDriver won't run for it and it would
                 // otherwise receive ZERO sends this pass, losing its AUTHORED subscriptions. Send the authored-only