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.Tests/ModbusTcpReconnectTests.cs

@@ -107,6 +107,7 @@ public sealed class ModbusTcpReconnectTests
         }
 
         /// <summary>Stops the server and releases resources.</summary>
+        /// <returns>A task that represents the asynchronous dispose operation.</returns>
         public async ValueTask DisposeAsync()
         {
             _stop.Cancel();
@@ -116,6 +117,7 @@ public sealed class ModbusTcpReconnectTests
     }
 
     /// <summary>Verifies that the transport recovers from a mid-session socket drop with auto-reconnect enabled.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Transport_recovers_from_mid_session_drop_and_retries_successfully()
     {
@@ -136,6 +138,7 @@ public sealed class ModbusTcpReconnectTests
     }
 
     /// <summary>Verifies that socket drops propagate to the caller when auto-reconnect is disabled.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Transport_without_AutoReconnect_propagates_drop_to_caller()
     {