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/ModbusLoggerInjectionTests.cs

@@ -42,7 +42,7 @@ public sealed class ModbusLoggerInjectionTests
         private sealed class NullScope : IDisposable
         {
             public static readonly NullScope Instance = new();
-            /// <inheritdoc />
+            /// <summary>Disposes the scope (no-op).</summary>
             public void Dispose() { }
         }
     }
@@ -52,15 +52,9 @@ public sealed class ModbusLoggerInjectionTests
     {
         /// <summary>Gets or sets the protected address.</summary>
         public ushort ProtectedAddress { get; set; } = 102;
-        /// <summary>Simulates connecting to the Modbus device.</summary>
-        /// <param name="ct">The cancellation token.</param>
-        /// <returns>A completed task.</returns>
+        /// <inheritdoc />
         public Task ConnectAsync(CancellationToken ct) => Task.CompletedTask;
-        /// <summary>Simulates sending a Modbus PDU.</summary>
-        /// <param name="unitId">The Modbus unit ID.</param>
-        /// <param name="pdu">The protocol data unit.</param>
-        /// <param name="ct">The cancellation token.</param>
-        /// <returns>The response PDU.</returns>
+        /// <inheritdoc />
         public Task<byte[]> SendAsync(byte unitId, byte[] pdu, CancellationToken ct)
         {
             var addr = (ushort)((pdu[1] << 8) | pdu[2]);
@@ -71,12 +65,13 @@ public sealed class ModbusLoggerInjectionTests
             resp[0] = pdu[0]; resp[1] = (byte)(qty * 2);
             return Task.FromResult(resp);
         }
-        /// <summary>Disposes the transport asynchronously.</summary>
+        /// <summary>Disposes the test transport stub.</summary>
         /// <returns>A completed value task.</returns>
         public ValueTask DisposeAsync() => ValueTask.CompletedTask;
     }
 
     /// <summary>Verifies first failure emits single warning and subsequent refires stay quiet.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task First_Failure_Emits_Single_Warning_Subsequent_Refire_Stays_Quiet()
     {
@@ -108,6 +103,7 @@ public sealed class ModbusLoggerInjectionTests
     }
 
     /// <summary>Verifies reprobe clearing prohibition emits information log.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Reprobe_Clearing_Prohibition_Emits_Information_Log()
     {