docs(scripts): correct frank-archon's step-sharing and slot-count comments

The env comment claimed BUSY_PREFILL_CHUNK=auto protects decode rows; the 1.8.1
source (core/sched/scheduler.cpp busy_cap) reserves 1+spec rows per decoding
sequence and 1/8 of the budget per waiting request, and refuses to shrink the
chunk for decoders alone -- auto is a prefill-speed dial. The interleave comment
carried a 512 that is not this build's auto value (0 until the held-step
counter asks; 64 in help mode). The serve header still described three decode
slots; MAX_SEQS has been 2 since the 2026-10-19 reslice. No behavior change.

scripts/frank-archon.env

@@ -93,14 +93,21 @@ FRANK_ARCHON_SPEC_TOKENS=2
 FRANK_ARCHON_MAX_BATCHED_TOKENS=2048
 # Step sharing. A prefill chunk that shares a step with decoding sequences holds
 # the device for the chunk's whole time, and every decode row in that step waits
-# that long for its next token (the census: [[LLM Performance Diagnosis]] §9).
-# `auto` leaves each decode row behind the chunk a row plus its draft window and
-# keeps a share for whatever is waiting to be admitted; a number pins the chunk's
-# cap; `off` is the pre-1.4 behaviour this endpoint ran for two eras, where the
-# chunk took the step and admission never ran. Interleave inserts N decode-only
-# steps after a chunk step taken beside decoders: it protects their cadence and
-# holds a waiting request out of those steps, so it stays 0 until the post-migration
-# decode-vs-prefill buckets say it is wanted.
+# that long for its next token: measured at this shape, decode-only steps 15.5 ms
+# against chunk steps 166 ms, which is the harness's ~146 t/s falling to ~11 t/s
+# while another session prefills (law and census: [[frank-archon]]).
+# `auto` is a PREFILL-SPEED dial, not a decoder dial: it reserves one row plus the
+# draft window per decoding sequence (3 tokens) and an eighth of the budget per
+# waiting request or waiting prefill, and the source states it will not halve for
+# decode rows alone. Live proof: prefill_chunks_capped 5,018 across 62,386 chunk
+# steps. A number is the only value that applies whenever the chunk shares a step,
+# and it must not go under the prefill stager's smallest pass -- 1025 rows here,
+# named on the boot line "prefill staging: ... a step of more than 1024 tokens" --
+# because below it every routed layer reads its pooled experts synchronously, so
+# 512 is a trap and the vendor measures the whole job slower there. Interleave
+# inserts N decode-only steps after a chunk step taken beside decoders: it protects
+# their cadence and holds a waiting request out of those steps. That is the decoder
+# dial, and it is 0 until the decode-vs-prefill buckets ask for it.
 FRANK_ARCHON_BUSY_PREFILL_CHUNK=auto
 FRANK_ARCHON_PREFILL_INTERLEAVE=0
 # Prefix cache: pinned host memory only. The disk tier was removed outright

scripts/serve-frank-archon.sh

@@ -15,13 +15,16 @@
 # 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): THREE 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 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 out of the log and check the pool still backs 3 x 200,000.
+# 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
+# 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
+# the two lines that size a prefill step — "activation arena: ... lends ... while
+# steps are at most N tokens" (the arena levels the expert slab borrows) and
+# "prefill staging: ... a step of more than N tokens ..." (the chunk size below which
+# 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 +