feat(gpu): relocate char-rp to GPU1 + re-optimize both ana-ml2 cards for max context

Operator-directed 2026-07-16. Moved the char-rp prose seat (Magidonia-24B,
llama-charrp) from GPU0 to GPU1 (CHARRP_GPU_ID 0->1; recreate llama-charrp
only -- the var is shared with the retired GGUF reasoning service), then
re-optimized every context-relevant seat on both cards to native/max context
with acceptable headroom:

  GPU0 (both seats now 256K native, ~14 GB reserve):
    - char-rp-reasoning 150K -> 256K  (heretic2 stack, util 0.38->0.46, 1.56x)
    - gen 256K, max-num-seqs 16 -> 32 (qwen36-27b-aeon, util 0.30->0.42, 5.43x)
  GPU1 (~6.7 GB headroom):
    - granite 64K -> 128K full-chapter (vllm stack, util 0.18->0.27, 1.50x)
    - char-rp 128K native (4 slots), selene/reward/embed/rerank unchanged

All seats gateway-verified healthy. Live .env changes on ana-ml2 with per-stack
backups (*-20260716). Templates updated to match; the qwen36-27b-aeon template
carries a NOTE that its served-name/model still lag the 2026-07-08 gen model swap
(35B-A3B-heretic) -- separate reconciliation. persistent-memory records the full
layout + the util-floor / per-model-KV-cost lessons.

Note: the heretic2-charrp-reasoning stack (char-rp-reasoning's live config) is
still untracked in git -- standing open-loop, its .env change lives server-side only.

stacks/vllm/.env.example

@@ -96,7 +96,9 @@ GRANITE_SERVED_NAME=granite-4.1-8b
 # 65536 — REDUCED 2026-06-14 (was 131072) to free GPU-1 room for the FP8 vision
 # model (Qwen3.6-35B-A3B, stacks/qwen36-vl, ~34 GB weights). Summarizer load is
 # short parallel calls, so the 64K cap is ample.
-GRANITE_MAX_MODEL_LEN=65536
+# 131072 — RESTORED 2026-07-16 (native max) for full-chapter summarization; GPU-1
+# freed by the image-bench evict + qwen36-vl gone, so the 128K ctx fits again.
+GRANITE_MAX_MODEL_LEN=131072
 # FP8 KV cache (native on Blackwell cc 12.0). At 50K ≈ ~4.2 GB (vs ~8.4 GB at fp16).
 GRANITE_KV_CACHE_DTYPE=fp8
 # util 0.35 (~33.6 GB) — tuned 2026-06-13 to leave ~3.5 GB free on GPU 1 alongside
@@ -113,4 +115,7 @@ GRANITE_KV_CACHE_DTYPE=fp8
 # calls; ample). Effective slope on this shared card ≈ 950 MiB KV per 0.01 util, and
 # KV must hold >= 1x max-model-len — util 0.15 undershot (crash: est max-len 47184 <
 # 65536), 0.18 lands the target cleanly.
-GRANITE_GPU_MEM_UTIL=0.18
+# 0.27 — RE-GROWN 2026-07-16 (same session) after char-rp moved onto GPU-1: spend the
+# leftover room on full-chapter context (max-len 131072). KV 15.0 GiB = 196,560 tokens
+# = 1.50x @ 131072; GPU-1 lands ~6.7 GB headroom (char-rp 30 + granite 27 + selene 17 + trio).
+GRANITE_GPU_MEM_UTIL=0.27