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/TwinCATDriverPageFormSerializationTests.cs

@@ -14,6 +14,7 @@ public sealed class TwinCATDriverPageFormSerializationTests
         WriteIndented = false,
     };
 
+    /// <summary>Verifies that serializing and deserializing TwinCAT driver options preserves all known fields.</summary>
     [Fact]
     public void RoundTrip_PreservesKnownFields()
     {
@@ -51,6 +52,7 @@ public sealed class TwinCATDriverPageFormSerializationTests
         back.Tags.ShouldBeEmpty();
     }
 
+    /// <summary>Verifies that deserializing JSON with unknown fields silently drops the unrecognized members.</summary>
     [Fact]
     public void Deserialize_DropsUnknownFields()
     {
@@ -64,6 +66,7 @@ public sealed class TwinCATDriverPageFormSerializationTests
         back.ProbeTimeoutSeconds.ShouldBe(25);
     }
 
+    /// <summary>Verifies that the form model round-trip preserves all editable fields.</summary>
     [Fact]
     public void FormModel_RoundTrip_PreservesEditableFields()
     {
@@ -96,6 +99,7 @@ public sealed class TwinCATDriverPageFormSerializationTests
         roundTripped.ProbeTimeoutSeconds.ShouldBe(15);
     }
 
+    /// <summary>Verifies that a device row round-trip preserves all editable fields.</summary>
     [Fact]
     public void DeviceRow_RoundTrip_PreservesEditableFields()
     {
@@ -109,6 +113,7 @@ public sealed class TwinCATDriverPageFormSerializationTests
         back.DeviceName.ShouldBe("PLC1");
     }
 
+    /// <summary>Verifies that unedited source fields are carried through after a device row edit.</summary>
     [Fact]
     public void DeviceRow_CarriesThroughUneditedSourceFields()
     {
@@ -124,6 +129,7 @@ public sealed class TwinCATDriverPageFormSerializationTests
         back.DeviceName.ShouldBe("Renamed");
     }
 
+    /// <summary>Verifies that device row validation rejects duplicate host addresses.</summary>
     [Fact]
     public void DeviceRow_ValidateRow_RejectsDuplicateHostAddress()
     {
@@ -140,6 +146,7 @@ public sealed class TwinCATDriverPageFormSerializationTests
         error.ShouldContain("Duplicate");
     }
 
+    /// <summary>Verifies that a tag row round-trip preserves all editable fields.</summary>
     [Fact]
     public void TagRow_RoundTrip_PreservesEditableFields()
     {
@@ -156,6 +163,7 @@ public sealed class TwinCATDriverPageFormSerializationTests
         back.Writable.ShouldBeFalse();
     }
 
+    /// <summary>Verifies that the unedited WriteIdempotent field is carried through after a tag row edit.</summary>
     [Fact]
     public void TagRow_CarriesThroughUneditedWriteIdempotent()
     {
@@ -172,6 +180,7 @@ public sealed class TwinCATDriverPageFormSerializationTests
         back.WriteIdempotent.ShouldBeTrue();
     }
 
+    /// <summary>Verifies that tag row validation rejects duplicate tag names (case-insensitive).</summary>
     [Fact]
     public void TagRow_ValidateRow_RejectsDuplicateName()
     {
@@ -189,6 +198,7 @@ public sealed class TwinCATDriverPageFormSerializationTests
         error.ShouldContain("Duplicate");
     }
 
+    /// <summary>Verifies that ToOptions serializes device and tag lists correctly.</summary>
     [Fact]
     public void FormModel_ToOptions_SerializesDeviceAndTagLists()
     {