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/CommandBaseTests.cs

@@ -9,6 +9,7 @@ namespace ZB.MOM.WW.OtOpcUa.Client.CLI.Tests;
 public class CommandBaseTests
 {
     /// <summary>Verifies that common options map to connection settings correctly.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task CommonOptions_MapToConnectionSettings_Correctly()
     {
@@ -39,6 +40,7 @@ public class CommandBaseTests
     }
 
     /// <summary>Verifies that encrypt option maps to SignAndEncrypt.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task SecurityOption_Encrypt_MapsToSignAndEncrypt()
     {
@@ -57,6 +59,7 @@ public class CommandBaseTests
     }
 
     /// <summary>Verifies that none option maps to None.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task SecurityOption_None_MapsToNone()
     {
@@ -75,6 +78,7 @@ public class CommandBaseTests
     }
 
     /// <summary>Verifies that no failover URLs results in null FailoverUrls.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task NoFailoverUrls_FailoverUrlsIsNull()
     {