docs: complete XML doc comments via fixdocs (2757 to 131 findings)

Add missing <returns>/<param>/<summary>/<typeparam> tags and clean up
misused inheritdoc across 481 files so the documented API surface is
complete. Documentation-only (zero code lines changed). The 131 remaining
findings are inheritdoc-style warnings deliberately left to preserve
hand-written implementation rationale (plan-decision notes, race-condition
explanations).

tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/OpcUaClientDriverPageFormSerializationTests.cs

@@ -17,6 +17,7 @@ public sealed class OpcUaClientDriverPageFormSerializationTests
         WriteIndented = false,
     };
 
+    /// <summary>Verifies that a round-trip serialization preserves all known driver option fields.</summary>
     [Fact]
     public void RoundTrip_PreservesKnownFields()
     {
@@ -68,6 +69,7 @@ public sealed class OpcUaClientDriverPageFormSerializationTests
         back.ProbeTimeoutSeconds.ShouldBe(20);
     }
 
+    /// <summary>Verifies that deserialization silently drops unknown fields.</summary>
     [Fact]
     public void Deserialize_DropsUnknownFields()
     {
@@ -83,6 +85,7 @@ public sealed class OpcUaClientDriverPageFormSerializationTests
         back.ProbeTimeoutSeconds.ShouldBe(20);
     }
 
+    /// <summary>Verifies that the form model round-trip preserves all driver option fields.</summary>
     [Fact]
     public void FormModel_RoundTrip_PreservesAllFields()
     {
@@ -156,6 +159,7 @@ public sealed class OpcUaClientDriverPageFormSerializationTests
         result.ProbeTimeoutSeconds.ShouldBe(25);
     }
 
+    /// <summary>Verifies that EndpointUrlRow.ToUrl trims leading and trailing whitespace.</summary>
     [Fact]
     public void EndpointUrlRow_FromUrl_ToUrl_Trims()
     {
@@ -165,6 +169,7 @@ public sealed class OpcUaClientDriverPageFormSerializationTests
         row.ToUrl().ShouldBe("opc.tcp://plc:4840");
     }
 
+    /// <summary>Verifies that ValidateRow rejects a blank URL.</summary>
     [Fact]
     public void EndpointUrlRow_ValidateRow_RejectsBlank()
     {
@@ -176,6 +181,7 @@ public sealed class OpcUaClientDriverPageFormSerializationTests
         error.ShouldBe("URL is required.");
     }
 
+    /// <summary>Verifies that ValidateRow rejects a URL with a non-opc.tcp scheme.</summary>
     [Fact]
     public void EndpointUrlRow_ValidateRow_RejectsNonOpcTcpScheme()
     {
@@ -187,6 +193,7 @@ public sealed class OpcUaClientDriverPageFormSerializationTests
         error.ShouldBe("Endpoint URL must start with opc.tcp://");
     }
 
+    /// <summary>Verifies that ValidateRow rejects a duplicate URL.</summary>
     [Fact]
     public void EndpointUrlRow_ValidateRow_RejectsDuplicate()
     {
@@ -204,6 +211,7 @@ public sealed class OpcUaClientDriverPageFormSerializationTests
         error.ShouldContain("Duplicate endpoint");
     }
 
+    /// <summary>Verifies that editing a row in-place does not flag it as a duplicate of itself.</summary>
     [Fact]
     public void EndpointUrlRow_ValidateRow_AllowsEditingRowInPlace()
     {
@@ -220,6 +228,7 @@ public sealed class OpcUaClientDriverPageFormSerializationTests
         error.ShouldBeNull();
     }
 
+    /// <summary>Verifies that an endpoint URL list round-trips and preserves the original order.</summary>
     [Fact]
     public void EndpointUrls_ListRoundTrip_PreservesOrder()
     {