docs(abcip): Large Forward Open refusal targets and ConnectionSize honouring (T21 review r1 M6)

The 5069-L3x supports the Large open, as the press proved. The narrow/refusing case is a pre-v20 1769-L3x or a bridge. AbCipDeviceOptions.ConnectionSize: the native transport honours it on the wire; libplctag ignores it.

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

docs/drivers/AbServer-Test-Fixture.md

@@ -120,7 +120,7 @@ happens when a non-safety write lands on a real `1756-L8xS` — is not exercised
 
 Since T21 the CompactLogix profile defaults to a **Large** Forward Open (4002), matching what libplctag
 opens for `plc=compactlogix`. The old 504 default was cosmetic under libplctag, which never received it,
-and cost the native transport ~3× the round trips per poll. A narrower 5069-L3x / pre-v20 target that refuses
+and cost the native transport ~3× the round trips per poll. A pre-v20 CompactLogix (1769-L3x) or a bridge that refuses
 the Large open is handled by `CipConnection`'s fallback (a regular open at min(size, 504) in the same
 throttled attempt). That fallback is pinned by unit tests against a fake target only: `ab_server` accepts
 any size, so a refusing controller is never exercised here.

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Contracts/AbCipDriverOptions.cs

@@ -129,11 +129,9 @@ public sealed class AbCipDriverOptions
 ///     touching every other device on the same family.</param>
 /// <param name="ConnectionSize">Per-device override for the Forward Open
 ///     ConnectionSize (Large Forward Open packet size in bytes). <c>null</c> inherits the family
-///     profile's <c>DefaultConnectionSize</c>. Honoured by the driver layer; the underlying
+///     profile's <c>DefaultConnectionSize</c>. The native transport honours it on the wire (its Forward
-///     libplctag 1.5.2 wrapper has no direct <c>ConnectionSize</c> property, so the value is
+///     Open size). The libplctag transport ignores it: the libplctag 1.5.2 wrapper has no
-///     plumbed through <see cref="AbCipTagCreateParams"/> for forward-compat with future wrapper
+///     <c>ConnectionSize</c> property, so libplctag opens with its own size for the <c>plc</c> attribute.</param>
-///     versions or a custom tag-attribute path; current builds use the family profile default at
-///     the wire layer regardless.</param>
 public sealed record AbCipDeviceOptions(
     string HostAddress,
     AbCipPlcFamily PlcFamily = AbCipPlcFamily.ControlLogix,

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip/PlcFamilies/AbCipPlcFamilyProfile.cs

@@ -43,7 +43,7 @@ public sealed record AbCipPlcFamilyProfile(
         LibplctagPlcAttribute: "compactlogix",
         // Large Forward Open, matching libplctag: `plc=compactlogix` opens Large (0x5B, 4002) and the
         // native transport must not pack into a third of the window (T21 latency harness: 504 cost ~3x
-        // the round trips per poll). A narrower 5069-L3x / pre-v20 target that refuses the Large open
+        // the round trips per poll). A pre-v20 CompactLogix (1769-L3x) or a bridge that refuses the Large open
         // is covered by CipConnection's fallback — a regular open at min(size, 504) inside the same
         // throttled attempt. An explicit ConnectionSize (driver options or per device) still wins.
         DefaultConnectionSize: 4002,