docs: frank-large vLLM MiMo-BF16 runbook; retire the gufo runbook

New runbook carries the roof math, the measured three-arm spec table, the
greedy-text numerics trap, the reasoning-field contract change and the
rollback tag. LLM index and AGENTS.md fleet table, bench policy and runbook
index follow; the frank-small index entries catch up to the SGLang cutover
(entry was missed on 2026-10-01). Work log records the cutover.

serverAppConfigs-docs/log.md

@@ -875,3 +875,40 @@ any repo service.
   verified (KV cache size, concurrency, MNBT 1024, gather 32x64) plus live
   contract probes (reasoning split, tool_calls). Rollback target for the
   2026-09-29 fp8+MTP4 shape: git tag `frank-primary-fp8-mtp-20261001`.
+
+## 2026-10-01 — frank-large cutover: gufo -> vLLM TheRock, MiMo-V2.6 BF16 + cross-model MTP
+
+- **Question that started it:** can a Qwen3.5 MTP drafter attach to
+  frank-small, and how does vLLM run the FULL BF16 MiMo checkpoint? Answer 1:
+  not on frank-small — SGLang reads the MTP head from the TARGET checkpoint
+  and MiMo ships ZERO `mtp.*` tensors (base and INT8 alike). Answer 2: the
+  digest-pinned `kyuz0/vllm-therock-gfx1151` image (vLLM 0.30 / torch 2.11 /
+  TheRock ROCm 10) boots BF16 MiMo on the gfx1151 iGPU in ~200-240 s, and
+  vLLM reads the draft from a SEPARATE path — so cross-model MTP from
+  `Qwen/Qwen3.5-9B` (the distill's source, identical 4096/248320/32-layer
+  geometry) works. Frank's call: ship that as frank-large.
+- **Bench window (frank-large stopped, one session, temp 0, 28,647-token
+  prefill / 512 decode):** base 17,876 t/s prefill / 13.1 t/s decode (13.1
+  is ~94% of the LPDDR5x BF16 roof - decode here is bandwidth, not a bug);
+  +DFlash-8 7,976 / 17.4 (acceptance 59%/26% per position); +MTP-2 7,380 /
+  19.8 (71%/44%, token rate 57.4%). Deployed MTP-2: +51% decode. Both spec
+  arms pay ~55-59% of prefill. `num_speculative_tokens` beyond 2 unmeasured.
+- **Measured numerics law:** spec arms do NOT reproduce the no-spec greedy
+  text (bf16 batched verification reorders reductions; near-tie argmaxes
+  cascade). vLLM spec decode is distribution-preserving, not
+  bitwise-greedy-preserving.
+- **Client-contract delta wired:** vLLM emits `reasoning`, not
+  `reasoning_content` - `models.yml` frank-large block now sets
+  `reasoningContentField: "reasoning"`, and the extraBody moved to the
+  Qwen3.5-family recipe (0.7/0.8) with `chat_template_kwargs`
+  (a top-level `preserve_thinking` is ignored by vLLM).
+- Deployer gap found pre-deploy: the spec-draft gate demanded a single
+  `model.safetensors` (the dflash layout) and would have rejected the
+  deployed MTP arm (4 shards behind an index); fixed to accept both
+  layouts, gated by bats. `z-lab/Qwen3.5-9B-DFlash`'s "vLLM PR #40898
+  unmerged" card claim is FALSE - `vllm/v1/spec_decode/dflash.py` ships in
+  0.30 (verified in-image); the drafter stays on disk as the alternative.
+- Host state: +38 GiB fetched (MiMo BF16 17.53 GiB, Qwen3.5-9B 18 GiB,
+  DFlash 2.58 GiB), disk down to ~26 GiB free - reclaim pass due. gufo
+  rollback pinned at git tag `frank-large-gufo-q4kxl-20261001`; engine,
+  Q4_K_XL payload and DFlash2 drafter all remain on the host.