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/S7DriverPageFormSerializationTests.cs

@@ -15,6 +15,7 @@ public sealed class S7DriverPageFormSerializationTests
         WriteIndented = false,
     };
 
+    /// <summary>Verifies that serializing and deserializing S7 driver options preserves all known fields.</summary>
     [Fact]
     public void RoundTrip_PreservesKnownFields()
     {
@@ -54,6 +55,7 @@ public sealed class S7DriverPageFormSerializationTests
         back.Tags.ShouldBeEmpty();
     }
 
+    /// <summary>Verifies that deserializing JSON with unknown fields silently drops the unrecognized members.</summary>
     [Fact]
     public void Deserialize_DropsUnknownFields()
     {
@@ -67,6 +69,7 @@ public sealed class S7DriverPageFormSerializationTests
         back.ProbeTimeoutSeconds.ShouldBe(12);
     }
 
+    /// <summary>Verifies that the S7 form model round-trip preserves all editable fields including tags.</summary>
     [Fact]
     public void FormModel_RoundTrip_PreservesEditableFields()
     {
@@ -122,6 +125,7 @@ public sealed class S7DriverPageFormSerializationTests
         roundTripped.Tags[1].Writable.ShouldBeFalse();
     }
 
+    /// <summary>Verifies that an S7 tag row round-trip preserves all editable fields.</summary>
     [Fact]
     public void S7TagRow_RoundTrip_PreservesEditableFields()
     {
@@ -137,6 +141,7 @@ public sealed class S7DriverPageFormSerializationTests
         back.StringLength.ShouldBe(80);
     }
 
+    /// <summary>Verifies that unedited fields are carried through after an S7 tag row edit.</summary>
     [Fact]
     public void S7TagRow_CarriesThroughUneditedFields()
     {
@@ -154,6 +159,7 @@ public sealed class S7DriverPageFormSerializationTests
         back.WriteIdempotent.ShouldBeTrue();
     }
 
+    /// <summary>Verifies that S7 tag row validation rejects duplicate tag names.</summary>
     [Fact]
     public void S7TagRow_ValidateRow_RejectsDuplicateNames()
     {
@@ -180,6 +186,7 @@ public sealed class S7DriverPageFormSerializationTests
         S7DriverPage.S7TagRow.ValidateRow(ok, all, editIndex: 1).ShouldBeNull();
     }
 
+    /// <summary>Verifies that the tag list serialize round-trip preserves all tag definitions.</summary>
     [Fact]
     public void TagList_SerializeRoundTrip_PreservesTags()
     {