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/Cli/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli.Tests/SubscribeCommandConsoleHandlerTests.cs

@@ -30,6 +30,7 @@ public sealed class SubscribeCommandConsoleHandlerTests
             "Commands", "SubscribeCommand.cs"));
     }
 
+    /// <summary>Verifies that SubscribeCommand documents why OnDataChange uses synchronous console output.</summary>
     [Fact]
     public void SubscribeCommand_explains_why_OnDataChange_uses_console_Output_synchronously()
     {
@@ -41,6 +42,7 @@ public sealed class SubscribeCommandConsoleHandlerTests
         source.ShouldContain("IConsole");
     }
 
+    /// <summary>Verifies that SubscribeCommand serializes console writes with a lock.</summary>
     [Fact]
     public void SubscribeCommand_serialises_console_writes_with_a_lock()
     {