feat: althing v3.0.0 cutover (U9b) and the sec seat onto GPU0

Two operator-authorised changes on the same afternoon.

## althing v3 (U9b flag day, one-way, no rollback)

The post office replaced the v2 P2P bus on nh3-dev and nh3-extdev.
One container is the only stateful component; heralds are one per box
and dial out; waiters are one per session. Every v2 command was deleted
rather than deprecated, so a script calling althing-cli now fails loudly
instead of silently talking to nothing.

73 handles seeded from the v2 CLI, which is authoritative over the v2
database's 91 agent rows -- the extra 18 are superseded names, a typo,
an underscore variant, and two machine-qualified handles that v3 makes
a category error. Verified by set difference in both directions rather
than by counting; a peer's "72 rendered" was a line-count artifact.

Deleted 5,043 orphaned wake FIFOs. The reason there were five thousand
is that v2 named them per session with the PID and never reaped them;
v3 names them per handle, so the leak is bounded by construction. That
is a fix in v3, not a cleanup we performed.

nh3-extdev needed its own path: althing lives there as a system wheel
under /opt/uv-tools with entry points in /usr/local/bin, its daemons
were system units rather than user units, and uv is not on the login
user's PATH. Captured as a rerunnable playbook rather than shell
history.

The v2 database is left inert on disk. There is no import path and none
was improvised.

## sec onto GPU0

GPU1 carries the five resident fleet seats and had ~28 GB free against
the ~51 GB this seat reserves, so it could not start there at all. GPU0
has been idle since run 3c was stopped. The compose header, the GPU pin
default and the homepage label all carried the old card number and are
corrected together -- a label that names the wrong GPU is a record that
lies about where the work runs.

Both playbooks carry verify phases that assert effective state. Two of
those verifies failed on green deployments while I was writing them:
one used a Go template that collided with the runner's own {{ }}
substitution, one omitted --handle so it failed on identity rather than
reachability. Both are fixed with the reason recorded inline, because a
verify that reports FAILED on a working system trains you to ignore it.

persistent-memory.md

@@ -27,7 +27,7 @@ Sister repos (separate gitea repos, deployed by playbooks here):
 | `vh/vor` | Inquisitor UI sidecar (port 7879) | push-to-main → CI deploys (2026-04-29) |
 | `vh/nevermore` | Twice-daily LLM-curated briefing (port 8181, replaces news-digest) | push-to-main → CI deploys (2026-04-30) |
 | `vh/asset-engine` | Internal control plane over inference services (port 8200, LAN-direct) | push-to-main → CI deploys (2026-05-12) |
-| `vh/althing` | Lean trusted inter-agent message bus — **v2 "email model" (v2.0.0b2, 2026-07)**: per-box local-SQLite bus + courier/receiver for P2P over the 10.x net; pillars = open-loops / per-box herald + wake-listener / roaming owner API `/owner/*` / `althing-mcp` stdio surface. The v0.15 lean-bus cut RIPPED moderation / chamber / forseti-daemon / agent-runner / redis-valkey. | per-box `uv tool install` (NOT CI-deploy); **nh3-dev = the DEV box** (editable install of `~/development/althing`, gets new versions first); **nh3-extdev** a mesh peer (model B: althing-svc + shared `/srv/althing`) |
+| `vh/althing` | Lean trusted inter-agent message bus — **v3.0.0 "the post office" as of 2026-08-28 (U9b flag day, one-way, no rollback)**: ONE container on nh3-dev at `http://10.100.10.50:8390` is the only stateful component; `althing-po-herald` one per box; `althing-listen` one per session; `postbox` is the client. **Every v2 command was DELETED, not deprecated** — `althing-cli`→`postbox`, `althing-wake-listener`→`althing-listen`, `althing-light-monitor`/`althing-receiver` gone. Sessions need BOTH `ALTHING_POST_OFFICE` and `ALTHING_HANDLE`; there is no default address. ⚠ An unreachable post office is an OUTAGE, never an empty inbox. → `persistent-memory.d/2026-08-28-althing-v3-cutover.md` | per-box install (NOT CI-deploy); **nh3-dev** = container host + repo; **nh3-extdev** = system WHEEL at `/opt/uv-tools`, needs its own wheel install (`playbooks/nh3-extdev-althing-v3.yaml`) |
 | `vh/mead-hall` | Bifrost tool-provider sidecar (port 5173 on dev VM 10.100.10.50) | push-to-main → CI deploys (2026-05-16) |
 | `vh/skaldsong` | Wizard + reader surface (port 8300, ana-docker, registry-pull pattern) | push-to-main → CI deploys (2026-05-19) |
 | `vh/Worldtree` | Conversation API (corviduo-dev demo :8080 / personal :8081 / pinned :8082) — Heimdall auth, Bifrost integration. **gitea-runner builds on ana-docker**; claude-bot ADMIN collaborator (2026-06-20). Now v1.0.0b19. | push-to-main → CI build-and-deploy (runner on ana-docker) |
@@ -119,6 +119,7 @@ _State as left 2026-08-26 23:05 PDT (written 2026-08-27 07:27, corrected 10:5x)
 
 ## Recent decisions
 
+- `[2026-08-28]` **althing v3.0.0 flag day (U9b) executed — the post office replaced the P2P bus on both boxes, one-way.** 73 handles seeded and verified by set difference; 5,043 orphaned v2 wake FIFOs deleted (v2 named them per-session+PID and never reaped; v3 names them per-handle, so the leak is bounded by construction); v2 db left inert. → `persistent-memory.d/2026-08-28-althing-v3-cutover.md`
 - `[2026-08-28]` **nh3-dev's three OOM events attribute to CLAUDE CODE — and the "no kernel evidence" was a permissions artifact.** journald was persistent all along; `journalctl` silently shows only your own messages outside `adm`. Single CC sessions measured at 5.4-18.4 GB, so 27 GB is 3-4 mature sessions, not the ~66 a 408 MB estimate implies. sysstat + atop now instrument the ramp. → `persistent-memory.d/2026-08-28-nh3-dev-oom-attribution.md`
 - `[2026-08-27]` **Run 3 gated: the preregistered rule PASSED and a k=25 follow-up found a 44pp self-harm guardrail collapse — DO NOT SERVE.** A pooled preserve-list test structurally cannot see a single-axis collapse. → `persistent-memory.d/2026-08-27-run3-gate-safety-regression.md`
 - `[2026-08-27]` **The corpus mix was specified in a unit the optimiser never sees** — 45.8% dialogue by CONTEXT, 24.2% by LOSS. Harness now leads with loss share and calls context a memory budget (`dd5a12e`). → `persistent-memory.d/2026-08-27-mix-specified-in-the-wrong-unit.md`