docs: backfill XML documentation across 756 files

Adds <summary>, <param>, <typeparam>, and <inheritdoc/> tags to public
members surfaced by commentchecker — resolves 5,847 of 5,869 issues
(99.6%) across three /fixdocs passes.

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests/ModbusConnectionOptionsTests.cs

@@ -11,6 +11,7 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests;
 [Trait("Category", "Unit")]
 public sealed class ModbusConnectionOptionsTests
 {
+    /// <summary>Verifies that defaults match historical behaviour.</summary>
     [Fact]
     public void Defaults_Match_Historical_Behaviour()
     {
@@ -28,6 +29,7 @@ public sealed class ModbusConnectionOptionsTests
         opts.Reconnect.BackoffMultiplier.ShouldBe(2.0);
     }
 
+    /// <summary>Verifies that factory reads KeepAlive knobs from JSON.</summary>
     [Fact]
     public void Factory_Reads_KeepAlive_Knobs_From_Json()
     {
@@ -50,6 +52,7 @@ public sealed class ModbusConnectionOptionsTests
         opts.KeepAlive.RetryCount.ShouldBe(5);
     }
 
+    /// <summary>Verifies that factory reads IdleDisconnect from JSON.</summary>
     [Fact]
     public void Factory_Reads_IdleDisconnect_From_Json()
     {
@@ -62,6 +65,7 @@ public sealed class ModbusConnectionOptionsTests
         opts.IdleDisconnectTimeout.ShouldBe(TimeSpan.FromMinutes(2));
     }
 
+    /// <summary>Verifies that factory reads Reconnect backoff from JSON.</summary>
     [Fact]
     public void Factory_Reads_Reconnect_Backoff_From_Json()
     {
@@ -82,6 +86,7 @@ public sealed class ModbusConnectionOptionsTests
         opts.Reconnect.BackoffMultiplier.ShouldBe(1.5);
     }
 
+    /// <summary>Verifies that factory with empty JSON uses all defaults.</summary>
     [Fact]
     public void Factory_With_Empty_Json_Uses_All_Defaults()
     {