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/Phase7ComposerPurityTests.cs

@@ -6,6 +6,7 @@ namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests;
 
 public sealed class Phase7ComposerPurityTests
 {
+    /// <summary>Verifies empty inputs produce empty result.</summary>
     [Fact]
     public void Empty_inputs_produce_empty_result()
     {
@@ -19,6 +20,7 @@ public sealed class Phase7ComposerPurityTests
         result.ScriptedAlarmPlans.ShouldBeEmpty();
     }
 
+    /// <summary>Verifies same inputs in different order produce structurally equal results.</summary>
     [Fact]
     public void Same_inputs_in_different_order_produce_structurally_equal_results()
     {
@@ -44,6 +46,7 @@ public sealed class Phase7ComposerPurityTests
         r1.ScriptedAlarmPlans.ShouldBe(r2.ScriptedAlarmPlans);
     }
 
+    /// <summary>Verifies Compose is pure with identical repeated calls.</summary>
     [Fact]
     public void Compose_is_pure_repeated_call_returns_element_identical_output()
     {
@@ -61,6 +64,7 @@ public sealed class Phase7ComposerPurityTests
         r1.ScriptedAlarmPlans.ShouldBe(r2.ScriptedAlarmPlans);
     }
 
+    /// <summary>Verifies output is sorted by natural key.</summary>
     [Fact]
     public void Output_is_sorted_by_natural_key()
     {