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/Server/ZB.MOM.WW.OtOpcUa.ControlPlane.Tests/ServiceLevelCalculatorTests.cs

@@ -7,6 +7,8 @@ namespace ZB.MOM.WW.OtOpcUa.ControlPlane.Tests;
 
 public sealed class ServiceLevelCalculatorTests
 {
+    /// <summary>Verifies that non-Up member statuses return a service level of zero.</summary>
+    /// <param name="status">The Akka cluster member status to test.</param>
     [Theory]
     [InlineData(MemberStatus.Down)]
     [InlineData(MemberStatus.Removed)]
@@ -19,6 +21,7 @@ public sealed class ServiceLevelCalculatorTests
         sl.ShouldBe((byte)0);
     }
 
+    /// <summary>Verifies that a fully healthy non-leader member returns a service level of 240.</summary>
     [Fact]
     public void Fully_healthy_non_leader_returns_240()
     {
@@ -27,6 +30,7 @@ public sealed class ServiceLevelCalculatorTests
         sl.ShouldBe((byte)240);
     }
 
+    /// <summary>Verifies that a fully healthy role leader returns a service level of 250.</summary>
     [Fact]
     public void Fully_healthy_role_leader_returns_250()
     {
@@ -35,6 +39,7 @@ public sealed class ServiceLevelCalculatorTests
         sl.ShouldBe((byte)250);
     }
 
+    /// <summary>Verifies that a database reachable but stale returns a service level of 200.</summary>
     [Fact]
     public void Db_reachable_but_stale_returns_200()
     {
@@ -43,6 +48,7 @@ public sealed class ServiceLevelCalculatorTests
         sl.ShouldBe((byte)200);
     }
 
+    /// <summary>Verifies that an unreachable and stale database returns a service level of 100.</summary>
     [Fact]
     public void Db_unreachable_and_stale_returns_100()
     {
@@ -51,6 +57,7 @@ public sealed class ServiceLevelCalculatorTests
         sl.ShouldBe((byte)100);
     }
 
+    /// <summary>Verifies that an OPC UA probe failure on a non-stale database returns zero.</summary>
     [Fact]
     public void Opcua_probe_fail_when_not_stale_returns_zero()
     {
@@ -60,6 +67,7 @@ public sealed class ServiceLevelCalculatorTests
         sl.ShouldBe((byte)0);
     }
 
+    /// <summary>Verifies that a Joining member status is treated like Up for service level grading.</summary>
     [Fact]
     public void Joining_member_is_treated_like_Up_for_grading()
     {