docs(ipv6): close the NH3 multi-prefix question by operator ruling

The gateway has no IP-passthrough mode, confirmed by the operator with
admin access to it, so the inexpensive path of letting the UDM take the
delegation whole and carve it natively is unavailable at this site.

What remains is a separate DHCPv6 client presenting several identities,
which needs recabling to reach the gateway, splits routing so that one
device handles v4 and another v6, and above all moves IPv6 off the
UDM's zone firewall, leaving the entire policy to be rebuilt elsewhere
before any host could safely hold a globally routable address. The
operator has declined it and the LANs stay without v6.

The index entry also still asserted the superseded single-delegation
conclusion as fact; it now carries the corrected reading alongside the
ruling, so the finding and the decision not to act on it arrive
together rather than the first inviting a retry of the second.

persistent-memory.d/2026-08-17-fleet-ipv6-mesh.md

@@ -165,3 +165,21 @@ looks like BGW rationing rather than a provisioning-profile limit.
 
 Live state at correction time: `wan_dhcpv6_pd_size: 64`, `wan1 v6
 2600:1700:b25:c110::48`, all 5 NH3 LANs still `ipv6_interface_type: none`.
+
+### ⛔ CLOSED 2026-08-24 — operator ruling, do not re-raise
+
+The seven unclaimed `/64`s stay unclaimed. Two facts close it:
+
+- **The BGW has no IP-passthrough mode.** Operator confirmed, and we hold admin
+  on it — so the cheap path (let the UDM take the `/60` directly and carve it
+  natively, as it already does at ESH) does not exist here.
+- **The only remaining route is a multi-DUID DHCPv6 client on a VM**, which
+  requires re-cabling to reach the BGW's DHCPv6 server, split-stack routing
+  (UDM for v4, VM for v6), and — the actual cost — **rebuilding the whole IPv6
+  firewall policy in nftables on that VM**, because routing v6 around the UDM
+  bypasses its zone firewall entirely and would leave every LAN host globally
+  reachable.
+
+Operator's call: not worth it. **NH3 LANs stay `ipv6_interface_type: none`.**
+Do not re-propose on the strength of "there are seven free prefixes" — the
+prefixes are real, the firewall rebuild is why nobody wants them.

persistent-memory.md

@@ -166,7 +166,7 @@ no longer deployed sidecars here. See Recent decisions.)
 
 - `[2026-08-17]` **Gen seat swapped to `absolute-heresy` — and the three bugs the swap exposed are worth more than the swap.** Candidate `MuXodious/Qwen3.8-27B-absolute-heresy` (Heretic v1.4.0 + SOMPOA, T377) beat the incumbent on refusals AND KL simultaneously, which is the unusual part — those normally trade off. Validated on the probe port per operator ruling, promoted, all 7 aliases green. **Durable lessons banked:** (1) **A CPU-only MTP head hash can replace the ~56 GB bf16 acceptance gate.** The `Qwen3_5ForConditionalGeneration` wrapper never loads the MTP head, so PEFT merges / Heretic runs / llm-compressor passes all leave `mtp.*` pristine — hashing it against a head we have already measured (the incumbent's, 47.7%) answers the question for free. Predicted 47.7%, measured 47.2%. Saved downing meromero. Tool: `services/gen-seat-mixed-quant/compare_mtp_head.py` (hash bf16 via **uint8 reinterpret** — numpy has no bfloat16). (2) **`post_quant.py` assumed a standalone `model-mtp.safetensors`**; a full checkpoint keeps `mtp.*` in a NUMBERED shard, so the copy silently no-op'd while the index was still rewritten to point at a file that never existed — 15 unresolvable tensors behind a correct-looking tensor count. Its own FAILED-CHECKS assertion caught it; **that is why the check exists rather than an assumption**. Fixed to extract. (3) **A probe that does not mirror the live seat manufactures failures.** `serve_probe.sh` hardcoded `:latest` (seat is a pinned nightly for #51113), had no tool-call/reasoning parsers, and its `--speculative-config` JSON died twice on quoting — **bash BRACE-EXPANDS `{"a":1,"b":2}` on the comma** unless single-quoted at the REMOTE shell. Adding the seat's flags took the surface test from 5/6 to **6/6**; the "tool calling broken" result was pure probe config. Commits `7997f11`,`254c588`,`2c36028`,`b0c2d3d`,`993421b`.
 
-- `[2026-08-17]` **Fleet IPv6 mapped + the real VPN topology verified; the driver is CGNAT at ESH, not the WireGuard mesh.** New ESH fiber (installing 2026-08-18) lands the house behind **CGNAT**, which breaks **Site Magic** (NH3↔ESH `sdwan-mesh-tunnel`) on IPv4 — so IPv6 becomes load-bearing as the escape hatch, and that is its most likely first consumer. Topology as VERIFIED (a prior turn assumed wrong and was corrected): UniFi↔UniFi = **Site Magic**; colo↔UniFi = **IPsec IKEv2** (`pfi-ana-nh3` 158M/165M pkt = the workhorse, `ana-to-eshudm`); **WireGuard is an RA convention only, host-based on `ana-wg`** UDP 31337 behind a FortiGate VIP — the FortiGate never terminates WG (FortiOS 7.2 has none; 7.4 added it) so "upgrade the edge for WireGuard" is a **non-problem, do not re-derive**. IPv6 today: **NH3 WAN live** `2600:1700:b25:c110::48`, **colo none**, **ESH none**. **AT&T delegates exactly ONE /64** (`2600:1700:b25:c11f::/64`) — proven by forcing prefix-ID auto→`0` and watching the subnet NOT move, because the `c110`/`c11f` pattern otherwise reads convincingly as a /60. A mesh needs a routable **WAN** address, **not** PD. `ana-wg`'s WG socket is **already dual-stack** (`[::]:31337`) → v6 RA needs an address + a v6 port-forward, no WG reconfig. ⚠ UDM legacy `rest/firewallrule` returns **0 rules** (zone-based firewall) — use `v2/…/firewall-policies`; inbound v6 is default-deny and held. All three endpoints will be **dynamic** → extend the existing hostname pattern (`ana-fw`/`nh3.phasefinal.com`) to **AAAA**. Enabled PD on `nh3-iot` to measure, **reverted on operator instruction** (all 5 LANs back to `none`, verified). Also fixed: **`ana-wg` WireGuard key material was world-readable** (`wg0.conf` + `keys/*_priv` + `*_psk` + client `configs/*.conf` at 644) → now 600, dirs 700, service untouched. Detail → `persistent-memory.d/2026-08-17-fleet-ipv6-mesh.md`.
+- `[2026-08-17]` **Fleet IPv6 mapped + the real VPN topology verified; the driver is CGNAT at ESH, not the WireGuard mesh.** New ESH fiber (installing 2026-08-18) lands the house behind **CGNAT**, which breaks **Site Magic** (NH3↔ESH `sdwan-mesh-tunnel`) on IPv4 — so IPv6 becomes load-bearing as the escape hatch, and that is its most likely first consumer. Topology as VERIFIED (a prior turn assumed wrong and was corrected): UniFi↔UniFi = **Site Magic**; colo↔UniFi = **IPsec IKEv2** (`pfi-ana-nh3` 158M/165M pkt = the workhorse, `ana-to-eshudm`); **WireGuard is an RA convention only, host-based on `ana-wg`** UDP 31337 behind a FortiGate VIP — the FortiGate never terminates WG (FortiOS 7.2 has none; 7.4 added it) so "upgrade the edge for WireGuard" is a **non-problem, do not re-derive**. IPv6 today: **NH3 WAN live** `2600:1700:b25:c110::48`, **colo none**, **ESH none**. **AT&T delegates one /64 PER REQUEST** (`2600:1700:b25:c11f::/64`) — and the BGW holds the whole `/60`, rationing `c118`–`c11f` one at a time while keeping `c110`–`c117`. So eight /64s exist; UniFi just solicits once. ⛔ **CLOSED 2026-08-24 — operator ruling, do not re-raise:** the BGW has **no IP-passthrough** (operator confirmed, and we have admin on it), so the only route to the other seven is a multi-DUID DHCPv6 client on a VM — which means split-stack routing and rebuilding the entire v6 firewall policy off the UDM. Juice not worth the squeeze. NH3 LANs stay v6-off. A mesh needs a routable **WAN** address, **not** PD. `ana-wg`'s WG socket is **already dual-stack** (`[::]:31337`) → v6 RA needs an address + a v6 port-forward, no WG reconfig. ⚠ UDM legacy `rest/firewallrule` returns **0 rules** (zone-based firewall) — use `v2/…/firewall-policies`; inbound v6 is default-deny and held. All three endpoints will be **dynamic** → extend the existing hostname pattern (`ana-fw`/`nh3.phasefinal.com`) to **AAAA**. Enabled PD on `nh3-iot` to measure, **reverted on operator instruction** (all 5 LANs back to `none`, verified). Also fixed: **`ana-wg` WireGuard key material was world-readable** (`wg0.conf` + `keys/*_priv` + `*_psk` + client `configs/*.conf` at 644) → now 600, dirs 700, service untouched. Detail → `persistent-memory.d/2026-08-17-fleet-ipv6-mesh.md`.
 
 - `[2026-08-17]` **Gen-seat multi-day degeneration RESOLVED — two compounding real causes, not one; the meta-lesson is "a mitigation that HELPS but doesn't FIX means a second cause, not a wrong one."** vLLM `qwen3_5_mtp`×GDN bug (#51113, real, fixed by nightly) + AEON full-W4A4 being lowest-fidelity (W4A4<W4+FP8<W4+bf16) → ~15-20% stochastic degeneration. Fixed by mixed FP8-attn build on pinned nightly. AEON purged. Also banked: **stochastic (~15-20%) degeneration is invisible to a small synthetic probe — n=1 "clean" validated THREE non-fixes (MTP-off, APC-off, nightly-alone) that all failed in real use; get the operator's real transcript, do not trust your own probe.** Full → `docs/pfi/model-quantization-playbook.md` §3.8 (+ §3.7 MTP-multi-turn). Commits `d28a371`,`2f2bbce`,`2185964`.