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.Modbus.IntegrationTests/ModbusSimulatorFixture.cs

@@ -82,7 +82,8 @@ public sealed class ModbusSimulatorFixture : IAsyncDisposable
         }
     }
 
-    /// <inheritdoc />
+    /// <summary>Disposes the fixture asynchronously (no-op for this fixture).</summary>
+    /// <returns>A completed value task.</returns>
     public ValueTask DisposeAsync() => ValueTask.CompletedTask;
 }