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/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests/OpcPlcFixture.cs

@@ -100,6 +100,7 @@ public sealed class OpcPlcFixture : IAsyncDisposable
     /// <summary>
     /// Disposes the fixture resources (currently a no-op).
     /// </summary>
+    /// <returns>A completed value task.</returns>
     public ValueTask DisposeAsync() => ValueTask.CompletedTask;
 }
 

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests/OpcUaClientSmokeTests.cs

@@ -17,6 +17,7 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests;
 public sealed class OpcUaClientSmokeTests(OpcPlcFixture sim)
 {
     /// <summary>Verifies that the client can connect and read a node through the real OPC UA stack.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Client_connects_and_reads_StepUp_node_through_real_OPC_UA_stack()
     {
@@ -35,6 +36,7 @@ public sealed class OpcUaClientSmokeTests(OpcPlcFixture sim)
     }
 
     /// <summary>Verifies that the client can read a batch of varied types from the simulator.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Client_reads_batch_of_varied_types_from_live_simulator()
     {
@@ -60,6 +62,7 @@ public sealed class OpcUaClientSmokeTests(OpcPlcFixture sim)
     }
 
     /// <summary>Verifies that the client can subscribe to data changes from the live server.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Client_subscribe_receives_StepUp_data_changes_from_live_server()
     {