docs: backfill XML documentation across 756 files

Adds <summary>, <param>, <typeparam>, and <inheritdoc/> tags to public
members surfaced by commentchecker — resolves 5,847 of 5,869 issues
(99.6%) across three /fixdocs passes.

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus/IModbusTransport.cs

@@ -7,6 +7,9 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Modbus;
 /// </summary>
 public interface IModbusTransport : IAsyncDisposable
 {
+    /// <summary>Establishes a connection to the Modbus server.</summary>
+    /// <param name="ct">A cancellation token to observe for cancellation.</param>
+    /// <returns>A task representing the asynchronous connection operation.</returns>
     Task ConnectAsync(CancellationToken ct);
 
     /// <summary>
@@ -14,12 +17,20 @@ public interface IModbusTransport : IAsyncDisposable
     ///     Throws <see cref="ModbusException"/> when the server returns an exception PDU
     ///     (function code + 0x80 + exception code).
     /// </summary>
+    /// <param name="unitId">The Modbus unit identifier (slave address).</param>
+    /// <param name="pdu">The protocol data unit (function code and data) to send.</param>
+    /// <param name="ct">A cancellation token to observe for cancellation.</param>
+    /// <returns>A task representing the asynchronous send operation that returns the response PDU.</returns>
     Task<byte[]> SendAsync(byte unitId, byte[] pdu, CancellationToken ct);
 }
 
+/// <summary>Represents a Modbus protocol exception.</summary>
 public sealed class ModbusException(byte functionCode, byte exceptionCode, string message)
     : Exception(message)
 {
+    /// <summary>Gets the Modbus function code that caused the exception.</summary>
     public byte FunctionCode { get; } = functionCode;
+
+    /// <summary>Gets the Modbus exception code.</summary>
     public byte ExceptionCode { get; } = exceptionCode;
 }