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.OpcUaClient.Tests/OpcUaClientLowFindingsRegressionTests.cs

@@ -26,6 +26,7 @@ public sealed class OpcUaClientLowFindingsRegressionTests
     // The decision branches are pure logic; assert them against the SDK constants so a
     // regression rewriting `valueRank >= 0` shows up in CI.
 
+    /// <summary>Verifies that ValueRank constants match the OPC UA Part 3 specification values.</summary>
     [Fact]
     public void ValueRank_constants_have_the_OPCUA_Part3_spec_values()
     {
@@ -39,6 +40,9 @@ public sealed class OpcUaClientLowFindingsRegressionTests
         ValueRanks.OneDimension.ShouldBe(1);
     }
 
+    /// <summary>Verifies that IsArray decision matches the valueRank >= 0 boundary.</summary>
+    /// <param name="valueRank">The OPC UA value rank to test.</param>
+    /// <param name="expectedIsArray">Whether the value rank should be treated as an array.</param>
     [Theory]
     [InlineData(-3, false)] // ScalarOrOneDimension — conservatively treated as scalar
     [InlineData(-2, false)] // Any — conservatively treated as scalar
@@ -69,6 +73,7 @@ public sealed class OpcUaClientLowFindingsRegressionTests
     //       with the *same delegate instance*. Confirm that further notifications do not
     //       invoke the handler.
 
+    /// <summary>Verifies that RemoteSubscription record carries handler delegates for detachment.</summary>
     [Fact]
     public void RemoteSubscription_record_carries_handler_delegates_so_they_can_be_detached()
     {
@@ -95,6 +100,7 @@ public sealed class OpcUaClientLowFindingsRegressionTests
             "so UnsubscribeAsync/ShutdownAsync can detach the Notification delegate before disposing the session.");
     }
 
+    /// <summary>Verifies that RemoteAlarmSubscription record carries handler delegate for detachment.</summary>
     [Fact]
     public void RemoteAlarmSubscription_record_carries_handler_delegate_so_it_can_be_detached()
     {
@@ -114,6 +120,7 @@ public sealed class OpcUaClientLowFindingsRegressionTests
             "disposing the session.");
     }
 
+    /// <summary>Verifies that UnsubscribeAsync with unknown handle does not throw after the fix.</summary>
     [Fact]
     public async Task UnsubscribeAsync_unknown_handle_does_not_throw_after_fix()
     {
@@ -124,6 +131,7 @@ public sealed class OpcUaClientLowFindingsRegressionTests
             await drv.UnsubscribeAsync(new FakeHandle(), TestContext.Current.CancellationToken));
     }
 
+    /// <summary>Verifies that UnsubscribeAlarmsAsync with unknown handle does not throw after the fix.</summary>
     [Fact]
     public async Task UnsubscribeAlarmsAsync_unknown_handle_does_not_throw_after_fix()
     {
@@ -132,13 +140,17 @@ public sealed class OpcUaClientLowFindingsRegressionTests
             await drv.UnsubscribeAlarmsAsync(new FakeAlarmHandle(), TestContext.Current.CancellationToken));
     }
 
+    /// <summary>Fake subscription handle for testing.</summary>
     private sealed class FakeHandle : Core.Abstractions.ISubscriptionHandle
     {
+        /// <summary>Gets the diagnostic identifier for this handle.</summary>
         public string DiagnosticId => "fake-sub";
     }
 
+    /// <summary>Fake alarm subscription handle for testing.</summary>
     private sealed class FakeAlarmHandle : Core.Abstractions.IAlarmSubscriptionHandle
     {
+        /// <summary>Gets the diagnostic identifier for this handle.</summary>
         public string DiagnosticId => "fake-alarm-sub";
     }
 }