fix(opcua): equipment-tag planner diff + folder-scoped NodeIds (review findings)

Two bundle-review fixes + idempotency coverage:
- CRITICAL: the planner ignored EquipmentTags, so an incremental deploy changing only
  equipment tags produced an empty plan and HandleRebuild short-circuited before
  materialising them. Add TagId to EquipmentTagPlan + Added/Removed/ChangedEquipmentTags
  to Phase7Plan (diffed by TagId, in IsEmpty, driving Apply's needsRebuild) — mirroring
  the GalaxyTags treatment.
- IMPORTANT: equipment variable NodeId was the raw driver FullName, which collides across
  identical machines (e.g. two PLCs both exposing register 40001) — the second variable
  was silently dropped. NodeId is now folder-scoped (parent/Name); FullName stays on
  EquipmentTagPlan for the later values-routing milestone.
- Task 4: SDK-backed idempotency test (double-apply -> single variable); restart-safety
  confirmed (RestoreApplied reuses the same RebuildAddressSpace -> HandleRebuild path).
- Minor: align composer equipment-tag sort with the artifact decoder (coalesce FolderPath).

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DeploymentArtifactTests.cs

@@ -167,6 +167,7 @@ public sealed class DeploymentArtifactTests
         var c = DeploymentArtifact.ParseComposition(blob);
 
         var tag = c.EquipmentTags.ShouldHaveSingleItem();
+        tag.TagId.ShouldBe("tag-eq");
         tag.EquipmentId.ShouldBe("eq-1");
         tag.DriverInstanceId.ShouldBe("drv-modbus");
         tag.Name.ShouldBe("Speed");