feat: add JoeAppEngine OPC UA nodes, fix DCL auto-reconnect and quality push

- Add JoeAppEngine folder to OPC UA nodes.json (BTCS, AlarmCntsBySeverity, Scheduler/ScanTime)
- Fix DataConnectionActor: capture Self in PreStart for use from non-actor threads,
  preventing Self.Tell failure in Disconnected event handler
- Implement InstanceActor.HandleConnectionQualityChanged to mark attributes Bad on disconnect
- Fix LmxFakeProxy TagMapper to serialize arrays as JSON instead of "System.Int32[]"
- Allow DataType and DataSourceReference updates in TemplateService.UpdateAttributeAsync
- Update test_infra_opcua.md with JoeAppEngine documentation

tests/ScadaLink.CentralUI.Tests/ScadaLink.CentralUI.Tests.csproj

@@ -9,8 +9,10 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="bunit" Version="2.0.33-preview" />
     <PackageReference Include="coverlet.collector" Version="6.0.4" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageReference Include="NSubstitute" Version="5.3.0" />
     <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.1.4" />
   </ItemGroup>
@@ -19,6 +21,10 @@
     <Using Include="Xunit" />
   </ItemGroup>
 
+  <ItemGroup>
+    <FrameworkReference Include="Microsoft.AspNetCore.App" />
+  </ItemGroup>
+
   <ItemGroup>
     <ProjectReference Include="../../src/ScadaLink.CentralUI/ScadaLink.CentralUI.csproj" />
   </ItemGroup>