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/InputValidationErrorsTests.cs

@@ -14,6 +14,7 @@ namespace ZB.MOM.WW.OtOpcUa.Client.CLI.Tests;
 public class InputValidationErrorsTests
 {
     /// <summary>Verifies that HistoryReadCommand with invalid start time throws CommandException.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task HistoryReadCommand_InvalidStartTime_ThrowsCommandException()
     {
@@ -32,6 +33,7 @@ public class InputValidationErrorsTests
     }
 
     /// <summary>Verifies that HistoryReadCommand with invalid end time throws CommandException.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task HistoryReadCommand_InvalidEndTime_ThrowsCommandException()
     {
@@ -50,6 +52,7 @@ public class InputValidationErrorsTests
     }
 
     /// <summary>Verifies that HistoryReadCommand with invalid aggregate throws CommandException.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task HistoryReadCommand_InvalidAggregate_ThrowsCommandException()
     {
@@ -68,6 +71,7 @@ public class InputValidationErrorsTests
     }
 
     /// <summary>Verifies that ReadCommand with invalid node ID throws CommandException.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadCommand_InvalidNodeId_ThrowsCommandException()
     {
@@ -85,6 +89,7 @@ public class InputValidationErrorsTests
     }
 
     /// <summary>Verifies that SubscribeCommand with invalid node ID throws CommandException.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task SubscribeCommand_InvalidNodeId_ThrowsCommandException()
     {