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/ModbusSubscribeOptionsTests.cs

@@ -20,7 +20,13 @@ public sealed class ModbusSubscribeOptionsTests
         public ushort CurrentValue;
         public int WritesSent;
         public int FC06Count;
+        /// <summary>Establishes a connection (no-op for testing).</summary>
+        /// <param name="ct">The cancellation token.</param>
         public Task ConnectAsync(CancellationToken ct) => Task.CompletedTask;
+        /// <summary>Sends a Modbus PDU and returns a response.</summary>
+        /// <param name="unitId">The Modbus unit ID.</param>
+        /// <param name="pdu">The protocol data unit to send.</param>
+        /// <param name="ct">The cancellation token.</param>
         public Task<byte[]> SendAsync(byte unitId, byte[] pdu, CancellationToken ct)
         {
             switch (pdu[0])
@@ -45,9 +51,11 @@ public sealed class ModbusSubscribeOptionsTests
                     return Task.FromResult(new byte[] { pdu[0], 0, 0 });
             }
         }
+        /// <summary>Disposes the transport (no-op for testing).</summary>
         public ValueTask DisposeAsync() => ValueTask.CompletedTask;
     }
 
+    /// <summary>Verifies that deadband filter suppresses changes below the threshold.</summary>
     [Fact]
     public async Task Deadband_Suppresses_SubThreshold_Changes()
     {
@@ -88,6 +96,7 @@ public sealed class ModbusSubscribeOptionsTests
         publishes.ShouldNotContain((short)107);
     }
 
+    /// <summary>Verifies that null deadband publishes every value change.</summary>
     [Fact]
     public async Task Deadband_Null_Publishes_Every_Change()
     {
@@ -112,6 +121,7 @@ public sealed class ModbusSubscribeOptionsTests
         publishes.ShouldContain((short)101);
     }
 
+    /// <summary>Verifies that WriteOnChangeOnly suppresses writes with identical repeated values.</summary>
     [Fact]
     public async Task WriteOnChangeOnly_Suppresses_Identical_Repeated_Writes()
     {
@@ -130,6 +140,7 @@ public sealed class ModbusSubscribeOptionsTests
         fake.WritesSent.ShouldBe(2, "two distinct values written; identical-value repeats suppressed");
     }
 
+    /// <summary>Verifies that WriteOnChangeOnly defaults to false and writes all values.</summary>
     [Fact]
     public async Task WriteOnChangeOnly_Default_False_Always_Writes()
     {
@@ -147,6 +158,7 @@ public sealed class ModbusSubscribeOptionsTests
         fake.WritesSent.ShouldBe(3, "default false → every write goes to the wire");
     }
 
+    /// <summary>Verifies that external reads invalidate the WriteOnChangeOnly cache.</summary>
     [Fact]
     public async Task WriteOnChangeOnly_Cache_Invalidated_By_Read_Divergence()
     {