fix(abcip): harden Ab.Transport CIP codec and EncapsulationClient (#564, #565)

CIP codec (#564): PatchU16 bounds guard; CipReply content equality; CipPath
port/length/ASCII/odd/oversize validation with ArgumentException for malformed
tag names and routes; CipPath.MessageRouter/ConnectionManager are now
ReadOnlySpan<byte>; refused Forward Open surfaces ForwardOpenRefusedException
with structured general/extended status; test CaptureFile uses BinaryPrimitives.

EncapsulationClient (#565): frame write bounded by the exchange timeout, which
faults (never cancels) the connection; finite positive timeouts enforced at
every entry point; gate wait bounded by the timeout; deterministic reorder of
the 300 ms test; new dispose-during-drain, gate-wait and RegisterSession
zero-context tests.

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Tests/Captures/CaptureFileTests.cs

@@ -1,3 +1,4 @@
+using System.Buffers.Binary;
 using Shouldly;
 using Xunit;
 
@@ -36,7 +37,7 @@ public sealed class CaptureFileTests
         foreach (var f in frames)
         {
             f.Bytes.Length.ShouldBeGreaterThanOrEqualTo(24, name);
-            BitConverter.ToUInt16(f.Bytes, 2).ShouldBe((ushort)(f.Bytes.Length - 24), name);
+            BinaryPrimitives.ReadUInt16LittleEndian(f.Bytes.AsSpan(2)).ShouldBe((ushort)(f.Bytes.Length - 24), name);
         }
     }
 
@@ -54,12 +55,12 @@ public sealed class CaptureFileTests
     [MemberData(nameof(AllCaptures))]
     public void Every_CPF_item_walk_ends_exactly_at_the_frame_end(string name)
     {
-        foreach (var f in CaptureFile.Load(name).Where(f => BitConverter.ToUInt16(f.Bytes, 0) is 0x6F or 0x70))
+        foreach (var f in CaptureFile.Load(name).Where(f => BinaryPrimitives.ReadUInt16LittleEndian(f.Bytes.AsSpan(0)) is 0x6F or 0x70))
         {
             var pos = 24 + 4 + 2;
-            var itemCount = BitConverter.ToUInt16(f.Bytes, pos);
+            var itemCount = BinaryPrimitives.ReadUInt16LittleEndian(f.Bytes.AsSpan(pos));
             pos += 2;
-            for (var i = 0; i < itemCount; i++) pos += 4 + BitConverter.ToUInt16(f.Bytes, pos + 2);
+            for (var i = 0; i < itemCount; i++) pos += 4 + BinaryPrimitives.ReadUInt16LittleEndian(f.Bytes.AsSpan(pos + 2));
 
             pos.ShouldBe(f.Bytes.Length, name);
         }