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.OpcUaServer.Tests/SdkServiceLevelPublisherTests.cs

@@ -19,6 +19,7 @@ public sealed class SdkServiceLevelPublisherTests : IDisposable
         Path.GetTempPath(),
         $"otopcua-pki-{Guid.NewGuid():N}");
 
+    /// <summary>Verifies that the publisher writes values to the standard Server.ServiceLevel variable.</summary>
     [Fact]
     public async Task Publish_writes_value_to_Server_ServiceLevel_variable()
     {
@@ -47,6 +48,7 @@ public sealed class SdkServiceLevelPublisherTests : IDisposable
         variable.Value.ShouldBe((byte)200);
     }
 
+    /// <summary>Verifies that publishing service level values is idempotent when called multiple times.</summary>
     [Fact]
     public async Task Publish_is_idempotent_when_called_multiple_times()
     {
@@ -83,6 +85,7 @@ public sealed class SdkServiceLevelPublisherTests : IDisposable
         return port;
     }
 
+    /// <summary>Disposes and cleans up the test resources.</summary>
     public void Dispose()
     {
         if (Directory.Exists(_pkiRoot))