docs(ab): hw4 evidence fix round 1 - bit-write gap provenance, README/CLI/fixture docs, libplctag-deletion gap

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

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip.IntegrationTests/Differential/EvidenceTests.cs

@@ -193,6 +193,7 @@ public sealed class EvidenceTests
                 $"max={(ids.Count > 0 ? ids.Max() : 0)} more={more} ascending={strictly} ids=[{sample}]");
         }
         Log($"Non-ascending pages: {nonAscending}");
+        Log(nonAscending == 0 ? "RESULT: every listing page strictly ascending." : $"RESULT: {nonAscending} NON-ASCENDING page(s) observed.");
         pages.ShouldNotBeEmpty();
         opens.ShouldBe(1);
     }

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.IntegrationTests/Docker/README.md

@@ -121,11 +121,17 @@ trip cleanly across SLC500, MicroLogix, and PLC-5 modes.
 
 ### Bit-file writes on ab_server
 
-`B3:0/5`-style bit-in-boolean writes currently surface `0x803D0000`
-against `ab_server --plc=SLC500`; bit reads work. Non-blocking for the
-smoke suite (which targets N-file Int16 + F-file float reads), but
-bit-write fidelity isn't simulator-verified — route operator-critical
-bit writes to real hardware or RSEmulate 500 until upstream resolves.
+Originally (May 2026, libplctag only, before the native transport) a `B3:0/5`
+bit write surfaced `0x803D0000` against `ab_server --plc=SLC500`. **That does
+not reproduce any more** (2026-10-09): `AbLegacyBitWriteTests` writes `B3:0`,
+sets bit 5 and clears bit 3 and asserts the whole word each time, and passes
+on SLC500 and MicroLogix on both libplctag and native, and on PLC-5 with
+libplctag. The cause of the original failure was never determined (the
+driver's parent-word read-modify-write and ab_server's PCCC handlers are
+both unchanged in shape, so an older libplctag/driver path is the likely
+difference). PLC-5 on the native transport returns `0x803D0000`
+(`BadNotSupported`) for a different reason: all native PLC-5 writes are
+refused before the wire (#571); the test pins that.
 
 ### Other known gaps (unchanged from ab_server)