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/ModbusBitRmwTests.cs

@@ -14,8 +14,16 @@ public sealed class ModbusBitRmwTests
         public readonly ushort[] HoldingRegisters = new ushort[256];
         public readonly List<byte[]> Pdus = new();
 
+        /// <summary>Connects asynchronously (no-op for fake).</summary>
+        /// <param name="ct">Cancellation token (unused).</param>
+        /// <returns>A completed task.</returns>
         public Task ConnectAsync(CancellationToken ct) => Task.CompletedTask;
 
+        /// <summary>Sends a Modbus PDU and returns a response.</summary>
+        /// <param name="unitId">The Modbus unit ID (unused).</param>
+        /// <param name="pdu">The protocol data unit to send.</param>
+        /// <param name="ct">Cancellation token (unused).</param>
+        /// <returns>A task containing the response PDU.</returns>
         public Task<byte[]> SendAsync(byte unitId, byte[] pdu, CancellationToken ct)
         {
             Pdus.Add(pdu);
@@ -45,6 +53,8 @@ public sealed class ModbusBitRmwTests
             return Task.FromException<byte[]>(new NotSupportedException($"FC 0x{pdu[0]:X2} not supported by fake"));
         }
 
+        /// <summary>Disposes asynchronously (no-op for fake).</summary>
+        /// <returns>A completed task.</returns>
         public ValueTask DisposeAsync() => ValueTask.CompletedTask;
     }
 
@@ -60,6 +70,7 @@ public sealed class ModbusBitRmwTests
         return (new ModbusDriver(opts, "modbus-1", _ => fake), fake);
     }
 
+    /// <summary>Verifies that setting a bit reads the current register, ORs the bit, and writes back.</summary>
     [Fact]
     public async Task Bit_set_reads_current_register_ORs_bit_writes_back()
     {
@@ -78,6 +89,7 @@ public sealed class ModbusBitRmwTests
         fake.Pdus[1][0].ShouldBe((byte)0x06);
     }
 
+    /// <summary>Verifies that clearing a bit reads the current register, ANDs the bit off, and writes back.</summary>
     [Fact]
     public async Task Bit_clear_reads_current_register_ANDs_bit_off_writes_back()
     {
@@ -91,6 +103,7 @@ public sealed class ModbusBitRmwTests
         fake.HoldingRegisters[10].ShouldBe((ushort)0b1111_1111_1111_0111); // bit 3 cleared, rest preserved
     }
 
+    /// <summary>Verifies that concurrent bit writes to the same register preserve all updates via serialization.</summary>
     [Fact]
     public async Task Concurrent_bit_writes_to_same_register_preserve_all_updates()
     {
@@ -109,6 +122,7 @@ public sealed class ModbusBitRmwTests
         fake.HoldingRegisters[20].ShouldBe((ushort)0xFF); // all 8 bits set
     }
 
+    /// <summary>Verifies that bit writes to different registers proceed in parallel without contention.</summary>
     [Fact]
     public async Task Bit_write_on_different_registers_proceeds_in_parallel_without_contention()
     {
@@ -125,6 +139,7 @@ public sealed class ModbusBitRmwTests
             fake.HoldingRegisters[50 + i].ShouldBe((ushort)0x01);
     }
 
+    /// <summary>Verifies that bit writes preserve other bits in the same register.</summary>
     [Fact]
     public async Task Bit_write_preserves_other_bits_in_the_same_register()
     {