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.

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests/ModbusSubscriptionTests.cs

@@ -14,11 +14,18 @@ public sealed class ModbusSubscriptionTests
     ///     (Read Holding Registers) path is used. Mutating <see cref="HoldingRegisters"/>
     ///     between polls is how each test simulates a PLC value change.
     /// </summary>
+    /// <summary>Lightweight fake Modbus transport for testing subscriptions.</summary>
     private sealed class FakeTransport : IModbusTransport
     {
         public readonly ushort[] HoldingRegisters = new ushort[256];
+        /// <summary>Simulates connecting to the Modbus device.</summary>
+        /// <param name="ct">The cancellation token.</param>
         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>
         public Task<byte[]> SendAsync(byte unitId, byte[] pdu, CancellationToken ct)
         {
             if (pdu[0] != 0x03) return Task.FromException<byte[]>(new NotSupportedException("FC not supported"));
@@ -34,6 +41,7 @@ public sealed class ModbusSubscriptionTests
             }
             return Task.FromResult(resp);
         }
+        /// <summary>Disposes the transport asynchronously.</summary>
         public ValueTask DisposeAsync() => ValueTask.CompletedTask;
     }
 
@@ -44,6 +52,7 @@ public sealed class ModbusSubscriptionTests
         return (new ModbusDriver(opts, "modbus-1", _ => fake), fake);
     }
 
+    /// <summary>Verifies initial poll raises OnDataChange for every subscribed tag.</summary>
     [Fact]
     public async Task Initial_poll_raises_OnDataChange_for_every_subscribed_tag()
     {
@@ -65,6 +74,7 @@ public sealed class ModbusSubscriptionTests
         await drv.UnsubscribeAsync(handle, CancellationToken.None);
     }
 
+    /// <summary>Verifies unchanged values do not raise after initial poll.</summary>
     [Fact]
     public async Task Unchanged_values_do_not_raise_after_initial_poll()
     {
@@ -82,6 +92,7 @@ public sealed class ModbusSubscriptionTests
         events.Count.ShouldBe(1); // only the initial-data push, no change events after
     }
 
+    /// <summary>Verifies value change between polls raises OnDataChange.</summary>
     [Fact]
     public async Task Value_change_between_polls_raises_OnDataChange()
     {
@@ -102,6 +113,7 @@ public sealed class ModbusSubscriptionTests
         events.Last().Snapshot.Value.ShouldBe((short)200);
     }
 
+    /// <summary>Verifies unsubscribe stops the polling loop.</summary>
     [Fact]
     public async Task Unsubscribe_stops_the_polling_loop()
     {
@@ -121,6 +133,7 @@ public sealed class ModbusSubscriptionTests
         events.Count.ShouldBe(countAfterUnsub);
     }
 
+    /// <summary>Verifies SubscribeAsync floors intervals below 100ms.</summary>
     [Fact]
     public async Task SubscribeAsync_floors_intervals_below_100ms()
     {
@@ -140,6 +153,7 @@ public sealed class ModbusSubscriptionTests
         events.Count.ShouldBe(1);
     }
 
+    /// <summary>Verifies multiple subscriptions fire independently.</summary>
     [Fact]
     public async Task Multiple_subscriptions_fire_independently()
     {