feat(otopcua): multi-device-per-driver FixedTree partition (follow-up E)

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/AddressSpaceComposer.cs

@@ -577,11 +577,23 @@ public static class AddressSpaceComposer
             var raw = hostEl.GetString();
             if (string.IsNullOrWhiteSpace(raw)) return null;
             // Deterministic normalization (trim + lower-case) so both seams produce the identical string.
-            return raw.Trim().ToLowerInvariant();
+            return NormalizeDeviceHost(raw);
         }
         catch (JsonException) { return null; }
     }
 
+    /// <summary>
+    ///     The SINGLE SOURCE OF TRUTH for device-host normalization: trims surrounding whitespace and
+    ///     lower-cases (invariant). <see cref="TryExtractDeviceHost"/> applies this to a <c>Device</c>'s
+    ///     parsed <c>HostAddress</c>, and the FixedTree-partition path (<c>DriverHostActor</c>) applies the
+    ///     SAME function to a driver-discovered device-host folder segment before comparing the two — so an
+    ///     <see cref="EquipmentNode.DeviceHost"/> and a captured folder segment for the same device compare
+    ///     equal regardless of case/whitespace. Idempotent (a value already normalized is unchanged).
+    /// </summary>
+    /// <param name="host">The raw host string (non-null; a non-empty <c>HostAddress</c> or folder segment).</param>
+    /// <returns>The normalized host (trimmed + lower-cased).</returns>
+    public static string NormalizeDeviceHost(string host) => host.Trim().ToLowerInvariant();
+
     /// <summary>Parses the optional <c>alarm</c> object from a tag's <c>TagConfig</c> JSON. Returns null
     /// when absent, non-object, or non-JSON (the tag is then a plain variable). Never throws. The
     /// artifact-decode side (<c>DeploymentArtifact.ExtractTagAlarm</c>) MUST parse identically (byte-parity).</summary>