docs: strip task-tracking IDs from code comments and fill missing XML docs

Tracking IDs are review bookkeeping that rots in shipped source; the rationale they tagged is kept. Comment-only change (CommentChecker 458 -> 16 false positives).

clients/dotnet/ZB.MOM.WW.MxGateway.Client.Tests/MxGatewaySecretRedactionTests.cs

@@ -8,6 +8,7 @@ namespace ZB.MOM.WW.MxGateway.Client.Tests;
 /// </summary>
 public sealed class MxGatewaySecretRedactionTests
 {
+    /// <summary>Test: Redact replaces every occurrence of secret.</summary>
     [Fact]
     public void Redact_ReplacesEveryOccurrenceOfSecret()
     {
@@ -19,6 +20,7 @@ public sealed class MxGatewaySecretRedactionTests
         Assert.Equal("pw=<redacted> retry pw=<redacted> again <redacted>", result);
     }
 
+    /// <summary>Test: Redact scrubs both secrets when one is substring of the other.</summary>
     [Fact]
     public void Redact_ScrubsBothSecretsWhenOneIsSubstringOfTheOther()
     {
@@ -33,6 +35,7 @@ public sealed class MxGatewaySecretRedactionTests
         Assert.DoesNotContain("secret", result, StringComparison.Ordinal);
     }
 
+    /// <summary>Test: Redact with null secrets array returns message unchanged.</summary>
     [Fact]
     public void Redact_WithNullSecretsArray_ReturnsMessageUnchanged()
     {
@@ -43,6 +46,7 @@ public sealed class MxGatewaySecretRedactionTests
         Assert.Equal(message, result);
     }
 
+    /// <summary>Test: Redact with empty secrets array returns message unchanged.</summary>
     [Fact]
     public void Redact_WithEmptySecretsArray_ReturnsMessageUnchanged()
     {
@@ -53,6 +57,7 @@ public sealed class MxGatewaySecretRedactionTests
         Assert.Equal(message, result);
     }
 
+    /// <summary>Test: Redact ignores whitespace only secret.</summary>
     [Fact]
     public void Redact_IgnoresWhitespaceOnlySecret()
     {
@@ -64,6 +69,7 @@ public sealed class MxGatewaySecretRedactionTests
         Assert.Equal(message, result);
     }
 
+    /// <summary>Test: Redacted preserves concrete subtype and does not chain secret bearing original.</summary>
     [Fact]
     public void Redacted_PreservesConcreteSubtypeAndDoesNotChainSecretBearingOriginal()
     {