refactor(otopcua): align device-host map parity + document EquipmentNode rebuild trade-off (follow-up E)

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

@@ -72,7 +72,17 @@ public sealed record UnsLineProjection(string UnsLineId, string UnsAreaId, strin
 /// multi-device driver by host. The value is normalized identically on both the live-edit composer and
 /// the artifact-decode sides (single source of truth: <see cref="AddressSpaceComposer.TryExtractDeviceHost"/>);
 /// the later partition task MUST normalize the driver-discovered device-host folder segment the same way
-/// (trim + lower-case) so the two compare equal.</para></summary>
+/// (trim + lower-case) so the two compare equal.</para>
+/// <para><b>Address-space-rebuild interaction (accepted trade-off).</b> These three fields participate in
+/// <see cref="EquipmentNode"/>'s record value-equality, which <c>AddressSpacePlan.Compute</c> uses to
+/// build its changed-equipment set. So editing a <c>Device</c>'s <c>DeviceConfig</c> host/port, or
+/// rebinding an equipment's <c>DriverInstanceId</c> / <c>DeviceId</c>, now yields an
+/// <see cref="EquipmentNode"/> delta that triggers a full structural address-space rebuild on the next
+/// deploy (a momentary subscription teardown for that equipment). This is a deliberate, accepted
+/// decision: it fires only on rare operator-initiated config edits at deploy time (routine redeploys of
+/// unchanged config are unaffected — the delta is empty), it is recoverable, and it is directionally
+/// correct for the multi-device FixedTree re-partition (a later task). <c>AddressSpacePlan</c> is left
+/// unchanged.</para></summary>
 public sealed record EquipmentNode(
     string EquipmentId,
     string DisplayName,
@@ -343,10 +353,16 @@ public static class AddressSpaceComposer
         // DeviceId → connection host, resolved once from each bound Device's schemaless DeviceConfig JSON
         // via the shared TryExtractDeviceHost (single source of truth + normalization for both this
         // composer and the artifact-decode mirror in DeploymentArtifact, so EquipmentNode.DeviceHost is
-        // byte-parity-equal). Ordinal comparer matches the decode-side map exactly.
+        // byte-parity-equal). This MUST match DeploymentArtifact.BuildDeviceHostMap semantics EXACTLY:
-        var deviceHostById = (devices ?? Array.Empty<Device>())
+        // Ordinal comparer, skip blank/whitespace DeviceIds, and LAST-WINS on a duplicate DeviceId (a
-            .Where(d => d.DeviceId != null)
+        // foreach assignment, NOT ToDictionary which would THROW on a dupe — diverging from the decode
-            .ToDictionary(d => d.DeviceId, d => TryExtractDeviceHost(d.DeviceConfig), StringComparer.Ordinal);
+        // side's last-wins). DeviceId is DB-unique so a dupe is defensive-only.
+        var deviceHostById = new Dictionary<string, string?>(StringComparer.Ordinal);
+        foreach (var d in devices ?? Array.Empty<Device>())
+        {
+            if (string.IsNullOrWhiteSpace(d.DeviceId)) continue;
+            deviceHostById[d.DeviceId] = TryExtractDeviceHost(d.DeviceConfig);
+        }
         var areas = unsAreas
             .OrderBy(a => a.UnsAreaId, StringComparer.Ordinal)
             .Select(a => new UnsAreaProjection(a.UnsAreaId, a.Name))