docs: complete XML doc comments via fixdocs (2757 to 131 findings)

Add missing <returns>/<param>/<summary>/<typeparam> tags and clean up
misused inheritdoc across 481 files so the documented API surface is
complete. Documentation-only (zero code lines changed). The 131 remaining
findings are inheritdoc-style warnings deliberately left to preserve
hand-written implementation rationale (plan-decision notes, race-condition
explanations).

tests/Client/ZB.MOM.WW.OtOpcUa.Client.CLI.Tests/SubscribeCommandTests.cs

@@ -8,6 +8,7 @@ namespace ZB.MOM.WW.OtOpcUa.Client.CLI.Tests;
 public class SubscribeCommandTests
 {
     /// <summary>Verifies that ExecuteAsync subscribes with the correct parameters.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Execute_SubscribesWithCorrectParameters()
     {
@@ -37,6 +38,7 @@ public class SubscribeCommandTests
     }
 
     /// <summary>Verifies that ExecuteAsync unsubscribes when cancellation is requested.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Execute_UnsubscribesOnCancellation()
     {
@@ -60,6 +62,7 @@ public class SubscribeCommandTests
     }
 
     /// <summary>Verifies that ExecuteAsync disconnects and disposes in a finally block.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Execute_DisconnectsInFinally()
     {
@@ -84,6 +87,7 @@ public class SubscribeCommandTests
     }
 
     /// <summary>Verifies that ExecuteAsync prints the correct subscription message.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Execute_PrintsSubscriptionMessage()
     {