feat(frank-archon): four decode slots over a >=700k-token KV pool

Frank's order: 4 slots, a 700k pool, round UP if the resolver cannot land it
exactly. The cache target is MAX_SEQS x MAX_MODEL_LEN, so the demand is
800,000 fp8 tokens; the resolver funds ~91-93 % of demand (three boots of
evidence on the endpoint page), which clears 700k, and the VRAM has to come
from the expert plane -- which has to go somewhere, so HOST_POOL_MIB moves with
it. expert_vram_floor (core/place/planner.cpp:100-104) is exactly
plane + 2 units - host_room, and the live boot ledger pins that plane at 67.60
GiB a rank (23.73 GiB floor at 44,928 of room), so 49,152 drops the floor to
19.61 GiB and leaves the cache ~6.9 GiB: enough for the whole target, with the
leftover returned to the experts.

Costs, both real: pinned host RAM 87.75 -> 96.0 GiB (the pool is pinned once per
rank) and ~3.2 GiB a card of expert residency, read over the x8 Gen5 link when
the router picks a host-resident expert. The boot ledger's vram_kv line is the
referee; if it comes back under 700,000 tokens HOST_POOL_MIB goes up 1024 and
this redeploys.

TTM_MIN_MIB 150,000 -> 162,000 for the new pin ledger (2 x pool + PLE 48,824 +
prefix 8,192 + MNBT 2,048 + the auto checkpoint store, now 40 slots of 112 MiB =
161,848 MiB), and the bats ledger guard now counts the checkpoint store because
it grows with the slot count. The two env-value assertions in that seam are
bumped with the values they guard.

scripts/serve-frank-archon.sh

@@ -15,9 +15,9 @@
 # log states every budget before anything is allocated (weights vs KV
 # split, the expert host pool's coverage of the worst case, the PLE pin,
 # the P2P answer per pair) — read it after every resize.
-# Deployed shape (2026-10-19, radiance 1.8.1): TWO decode slots x 200,000 tokens,
-# fp8 KV, 44 GiB/rank pinned expert pool, MTP depth 2, prefix cache in pinned host
-# RAM, PLE pinned in RAM. The per-card split between the expert slab and the KV
+# Deployed shape (2026-10-21, radiance 1.8.1): FOUR decode slots x 200,000 tokens over a
+# >= 700,000-token fp8 KV pool, 48 GiB/rank pinned expert pool, MTP depth 2, prefix cache
+# in pinned host RAM, PLE pinned in RAM. The per-card split between the expert slab and the KV
 # pool is NO LONGER an operator number — 1.3.0 removed the VRAM pair and the budget
 # resolver derives it from headroom, the cache bound and the host pool, so the slab
 # size and the pool's token count are LEDGER lines. After every boot read them, plus
@@ -27,9 +27,9 @@
 # pooled experts are read synchronously) — and the cache's session backing.
 #
 # The root unit (scripts/frank-archon.service, User=dank,
-# LimitMEMLOCK=infinity) grants the pin budget: 2 x 44 GiB expert pools +
-# the 47.7 GiB PLE table + 8 GiB prefix host tier — ~147 GiB of pinned
-# pages, which is ALSO why this script refuses to start when ttm's
+# LimitMEMLOCK=infinity) grants the pin budget: 2 x 48 GiB expert pools + the 47.7 GiB PLE
+# table + 8 GiB prefix host tier + the checkpoint store (slots x 112 MiB) — ~159 GiB of
+# pinned pages, which is ALSO why this script refuses to start when ttm's
 # pages_limit/pages_max cap is under FRANK_ARCHON_TTM_MIN_MIB (see below).
 set -euo pipefail