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.CLI.Tests/CliConfigTests.cs

@@ -0,0 +1,90 @@
+using ScadaLink.CLI;
+
+namespace ScadaLink.CLI.Tests;
+
+public class CliConfigTests
+{
+    [Fact]
+    public void Load_DefaultValues_WhenNoConfigExists()
+    {
+        // Clear environment variables that might affect the test
+        var origContact = Environment.GetEnvironmentVariable("SCADALINK_CONTACT_POINTS");
+        var origLdap = Environment.GetEnvironmentVariable("SCADALINK_LDAP_SERVER");
+        var origFormat = Environment.GetEnvironmentVariable("SCADALINK_FORMAT");
+
+        try
+        {
+            Environment.SetEnvironmentVariable("SCADALINK_CONTACT_POINTS", null);
+            Environment.SetEnvironmentVariable("SCADALINK_LDAP_SERVER", null);
+            Environment.SetEnvironmentVariable("SCADALINK_FORMAT", null);
+
+            var config = CliConfig.Load();
+
+            Assert.Equal(636, config.LdapPort);
+            Assert.True(config.LdapUseTls);
+            Assert.Equal("json", config.DefaultFormat);
+        }
+        finally
+        {
+            Environment.SetEnvironmentVariable("SCADALINK_CONTACT_POINTS", origContact);
+            Environment.SetEnvironmentVariable("SCADALINK_LDAP_SERVER", origLdap);
+            Environment.SetEnvironmentVariable("SCADALINK_FORMAT", origFormat);
+        }
+    }
+
+    [Fact]
+    public void Load_ContactPoints_FromEnvironment()
+    {
+        var orig = Environment.GetEnvironmentVariable("SCADALINK_CONTACT_POINTS");
+        try
+        {
+            Environment.SetEnvironmentVariable("SCADALINK_CONTACT_POINTS", "host1:8080,host2:8080");
+
+            var config = CliConfig.Load();
+
+            Assert.Equal(2, config.ContactPoints.Count);
+            Assert.Equal("host1:8080", config.ContactPoints[0]);
+            Assert.Equal("host2:8080", config.ContactPoints[1]);
+        }
+        finally
+        {
+            Environment.SetEnvironmentVariable("SCADALINK_CONTACT_POINTS", orig);
+        }
+    }
+
+    [Fact]
+    public void Load_LdapServer_FromEnvironment()
+    {
+        var orig = Environment.GetEnvironmentVariable("SCADALINK_LDAP_SERVER");
+        try
+        {
+            Environment.SetEnvironmentVariable("SCADALINK_LDAP_SERVER", "ldap.example.com");
+
+            var config = CliConfig.Load();
+
+            Assert.Equal("ldap.example.com", config.LdapServer);
+        }
+        finally
+        {
+            Environment.SetEnvironmentVariable("SCADALINK_LDAP_SERVER", orig);
+        }
+    }
+
+    [Fact]
+    public void Load_Format_FromEnvironment()
+    {
+        var orig = Environment.GetEnvironmentVariable("SCADALINK_FORMAT");
+        try
+        {
+            Environment.SetEnvironmentVariable("SCADALINK_FORMAT", "table");
+
+            var config = CliConfig.Load();
+
+            Assert.Equal("table", config.DefaultFormat);
+        }
+        finally
+        {
+            Environment.SetEnvironmentVariable("SCADALINK_FORMAT", orig);
+        }
+    }
+}