docs: the second kernel round on the bench (CAMPAIGN-LOG, BRINGUP item 21)

The 2026-08-24 second-round record on dev 20260824200726: the dmesg
lines gone, the UP kernel on the performance governor, the two-file
WL18xx firmware set, every port answering over IPv6 on the ULA, the
export, and the two leftovers (no GUA from the DHCPv6 server, the NVS
loader line that patch 0015 removes). Item 21 says what remains.

Docs only; no catalog consequence.

docs/BRINGUP.md

@@ -1552,10 +1552,16 @@ Open items only. Anything closed is in `CAMPAIGN-LOG.md`.
     grblHAL's TCP:23 and forgetest listening dual-stack); the log export
     carries `/sys/fs/pstore`; and the release rootfs drops nano/libmagic,
     the udev hardware database and urllib3's pyOpenSSL chain (~22 MB).
-    Owed on the bench: boot (dmesg without the three lines), a GUA on
-    wlan0 with each port answered over IPv6, `scaling_governor` reading
-    performance, Wi-Fi up without the NVS warning, an export that contains
-    the sysrq record, then the item-16 drill and the campaign.
+    Bench-validated on dev 20260824200726 (CAMPAIGN-LOG 2026-08-24, second
+    round): the three lines are gone, the kernel is UP at 996 MHz on the
+    performance governor, Wi-Fi is up on the two-file firmware set, every
+    port answers over IPv6 on the board's ULA, the export runs. Two things
+    remain from it: the DHCPv6 server answers NoAddrsAvail and the GUA
+    prefix is not autonomous, so the board holds no GUA until the network
+    side hands one out (the client is running and asking); and with no NVS
+    on the rootfs the firmware loader logs the missing file at ERR level,
+    which patch 0015 (wlcore asks for the optional file the quiet way)
+    removes on the next build. Then the item-16 drill and the campaign.
 
 **Deliberately not gated:** an armed GRBL job after an underrun cuts at the
 stale origin unless homing is required (GRBL mode permits unhomed cutting; the