Add ExtendedAttributes config toggle for system+user attributes

When GalaxyRepository.ExtendedAttributes is true, uses the extended
attributes query that includes both primitive (system) and dynamic
(user-defined) attributes. Default is false (dynamic only, preserving
existing behavior). Extended mode returns ~564 attributes vs ~48.

Adds PrimitiveName and AttributeSource fields to GalaxyAttributeInfo.
Includes 5 new unit tests and 6 new integration tests covering both
standard and extended attribute modes.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/ZB.MOM.WW.LmxOpcUa.Host/appsettings.json

@@ -22,7 +22,8 @@
   "GalaxyRepository": {
     "ConnectionString": "Server=localhost;Database=ZB;Integrated Security=true;",
     "ChangeDetectionIntervalSeconds": 30,
-    "CommandTimeoutSeconds": 30
+    "CommandTimeoutSeconds": 30,
+    "ExtendedAttributes": false
   },
   "Dashboard": {
     "Enabled": true,