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.Host.IntegrationTests/ClusterFormationTests.cs

@@ -11,6 +11,7 @@ namespace ZB.MOM.WW.OtOpcUa.Host.IntegrationTests;
 /// </summary>
 public sealed class ClusterFormationTests
 {
+    /// <summary>Verifies that two nodes form a 2-member cluster.</summary>
     [Fact]
     public async Task Two_nodes_form_a_2_member_cluster()
     {
@@ -27,6 +28,7 @@ public sealed class ClusterFormationTests
         aRoles.ShouldContain("driver");
     }
 
+    /// <summary>Verifies that both nodes see each other as role members.</summary>
     [Fact]
     public async Task Both_nodes_see_each_other_as_role_members()
     {