Path-based NodeIds — decouple client contract from driver address

The pre-refactor design minted OPC UA NodeIds directly from the driver's
FullReference (the native-address string). That had three long-term
problems:

1. OPC UA Part 3 §5.2.2 requires NodeIds to be immutable across a node's
   lifetime. A rename of the underlying device address — Galaxy attribute,
   S7 tag, Modbus register alias — changed the NodeId and broke every
   client that had pinned the previous identifier.
2. Two drivers with coincidentally-matching native addresses (e.g. `temp`
   in Modbus and `temp` in S7 under different Equipment rows) collided on
   the NodeId identifier.
3. TagConfig was being placed verbatim on the wire; for drivers whose
   TagConfig is JSON (every driver shipped today, per the
   CK_Tag_TagConfig_IsJson check constraint), clients saw the raw JSON
   blob as the NodeId string.

Refactor:

* DriverNodeManager.Variable now mints a stable path-based NodeId
  `{driverId}/{folder-path}/{browseName}` and records the driver-side
  FullReference in a new _fullRefByNodeId map. OnReadValue / OnWriteValue
  / ResolveFullRef look the FullReference up via that map instead of
  casting NodeId.Identifier. The old cast path is preserved as a
  fallback so any test fixture that still registers variables with
  FullRef-shaped NodeIds keeps working.

* EquipmentNodeWalker.AddTagVariable now extracts the cross-driver
  `FullName` field from Tag.TagConfig before handing the address to
  DriverAttributeInfo. Every shipped driver stores the wire reference in
  TagConfig[FullName]; falling back to the raw string covers any future
  driver that wants an opaque non-JSON address. ExtractFullName is
  exposed internal for unit coverage.

* scripts/e2e/test-galaxy.ps1 defaults updated to the new path-based
  NodeIds. Verified live against p7-smoke-galaxy on the dev box:
  `ns=2;s=p7-smoke-galaxy/lab-floor/galaxy-line/reactor-1/Source` reads
  return Status=0x00000000 with a real Galaxy byte-array value.

Test suite: 195/195 Core.Tests + 283/283 Server.Tests green. Five new
ExtractFullName / FullName-passthrough tests added.

Task #112 GA-3 — golden-path read verified end-to-end; remaining E2E
script stages still blocked on pre-existing issues (ScriptedAlarm
predicate NRE on empty upstream cache, PowerShell $changeLines.Count
guard), tracked separately.
Task #134 — complete.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/ZB.MOM.WW.OtOpcUa.Core.Tests/OpcUa/EquipmentNodeWalkerTests.cs

@@ -258,6 +258,57 @@ public sealed class EquipmentNodeWalkerTests
         v.AttributeInfo.ScriptedAlarmId.ShouldBeNull();
     }
 
+    [Fact]
+    public void ExtractFullName_unwraps_json_object_with_FullName_field()
+    {
+        EquipmentNodeWalker.ExtractFullName(
+            "{\"FullName\":\"MESReceiver_001.MoveInBatchID\",\"DataType\":\"Int32\"}")
+            .ShouldBe("MESReceiver_001.MoveInBatchID");
+    }
+
+    [Fact]
+    public void ExtractFullName_handles_S7_style_extra_fields()
+    {
+        EquipmentNodeWalker.ExtractFullName(
+            "{\"FullName\":\"DB1_DBW0\",\"Address\":\"DB1.DBW0\",\"DataType\":\"Int16\"}")
+            .ShouldBe("DB1_DBW0");
+    }
+
+    [Fact]
+    public void ExtractFullName_returns_raw_when_not_json()
+    {
+        // Drivers that opt out of JSON TagConfig still work — fallback preserves the literal
+        // string so the driver's IReadable sees whatever the row author stored.
+        EquipmentNodeWalker.ExtractFullName("raw-tag-ref").ShouldBe("raw-tag-ref");
+    }
+
+    [Fact]
+    public void ExtractFullName_returns_raw_when_json_missing_FullName_field()
+    {
+        EquipmentNodeWalker.ExtractFullName("{\"Address\":\"DB1.DBW0\"}")
+            .ShouldBe("{\"Address\":\"DB1.DBW0\"}");
+    }
+
+    [Fact]
+    public void Driver_tag_FullName_passes_through_from_TagConfig_json()
+    {
+        // The walker hands the driver the unwrapped FullName string so IReadable.ReadAsync
+        // sees the plain address, not the raw TagConfig JSON. Verifies the dispatch contract
+        // the path-based NodeId refactor relies on.
+        var eq = Eq("eq-1", "line-1", "oven-3");
+        var tag = NewTag("t-1", "Temp", "Int32", "plc-01", "eq-1",
+            tagConfig: "{\"FullName\":\"plc-01/HR200\",\"DataType\":\"Int32\"}");
+        var content = new EquipmentNamespaceContent(
+            [Area("area-1", "warsaw")], [Line("line-1", "area-1", "line-a")],
+            [eq], [tag]);
+
+        var rec = new RecordingBuilder("root");
+        EquipmentNodeWalker.Walk(rec, content);
+
+        var v = rec.Children[0].Children[0].Children[0].Variables.Single();
+        v.AttributeInfo.FullName.ShouldBe("plc-01/HR200");
+    }
+
     // ----- builders for test seed rows -----
 
     private static UnsArea Area(string id, string name) => new()
@@ -282,7 +333,8 @@ public sealed class EquipmentNodeWalkerTests
         MachineCode = "MC-" + name,
     };
 
-    private static Tag NewTag(string tagId, string name, string dataType, string address, string? equipmentId) => new()
+    private static Tag NewTag(string tagId, string name, string dataType, string address,
+        string? equipmentId, string? tagConfig = null) => new()
     {
         TagRowId = Guid.NewGuid(),
         GenerationId = 1,
@@ -292,7 +344,7 @@ public sealed class EquipmentNodeWalkerTests
         Name = name,
         DataType = dataType,
         AccessLevel = ZB.MOM.WW.OtOpcUa.Configuration.Enums.TagAccessLevel.ReadWrite,
-        TagConfig = address,
+        TagConfig = tagConfig ?? address,
     };
 
     // ----- recording IAddressSpaceBuilder -----