fix(ablegacy): final review I3 — default reverts to libplctag; Native is opt-in

On a wire the native PCCC path is proven only for N-file reads/writes and
one F8 read (ab_server). An absent transport key now resolves to Libplctag
for every family; explicit Native still wins and still warns once per
instance on PLC-5/LogixPccc. AdminUI dropdown, CLI help, evidence claims
(PcccFileType, AbLegacy.md wire-evidence table, release note) corrected:
S:0 (default probe) and B/T/C/R/S/L/ST/A/O/I are unverified natively.

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

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/AbLegacyDriver.cs

@@ -72,7 +72,7 @@ public sealed class AbLegacyDriver : IDriver, IReadable, IWritable, ITagDiscover
         // Chosen once here and held across ReinitializeAsync (Shutdown+Initialize): a changed
         // Transport in a reinit config is inert; a deploy recreates the instance instead.
         _transport = AbLegacyTransportResolver.Resolve(options);
-        _transportDescription = AbLegacyTransportResolver.Describe(options.Transport, _transport);
+        _transportDescription = AbLegacyTransportResolver.Describe(options.Transport);
         _tagFactory = tagFactory ?? (_transport == AbLegacyTransport.Native
             ? new NativeAbLegacyTagFactory()
             : new LibplctagLegacyTagFactory());
@@ -103,7 +103,7 @@ public sealed class AbLegacyDriver : IDriver, IReadable, IWritable, ITagDiscover
     // from the node log which stack serves this instance.
     private readonly AbLegacyTransport _transport;
 
-    // Configured-vs-effective rendering of _transport for the init log, e.g. "Native (default)".
+    // Configured-vs-effective rendering of _transport for the init log, e.g. "Libplctag (default)".
     private readonly string _transportDescription;
 
     // Set once the explicit-Native-on-a-limited-family Warning has been logged for this instance.
@@ -157,8 +157,8 @@ public sealed class AbLegacyDriver : IDriver, IReadable, IWritable, ITagDiscover
             if (HasConfigBody(driverConfigJson))
                 _options = AbLegacyDriverFactoryExtensions.ParseOptions(_driverInstanceId, driverConfigJson);
 
-            // The resolver only defaults a PLC-5 / LogixPccc driver to libplctag; an operator may still pick
-            // Native explicitly. Allowed, but the limitation is client-visible, so name it ONCE per instance —
+            // Native is opt-in for every family (the default is libplctag); an operator may pick it explicitly
+            // even for PLC-5 / LogixPccc. Allowed, but the limitation is client-visible, so name it ONCE per instance —
             // not on every init, which includes every comms-loss reconnect retry (Task 22 review r1 M4).
             if (!_limitedFamilyWarned
                 && _transport == AbLegacyTransport.Native