voices-seat: ship lv-hemingway (ckpt850), and replace the memorisation control that passed it

Live on vllm-voices (fv-ml1 GPU0 :8027) beside voices-base, lv-yarros and lv-bronte.
Healthy 190 s after recreate, four models served, GPU0 96,092 -> 96,090 MiB. The adapter
was verified byte-identical to checkpoint-850 by sha256 across both transfer hops, and the
seat was verified by generating, not by reading its config: base emits 170 words of <think>
planning and never writes the passage, lv-hemingway writes the scene.

Gate design was pre-registered before any generation existed (0bb4938). Three arms, 60
held-out beats, 4 seeds, 240 generations per arm.

  A. VOICE   PASS 6.4x   +0.413 delta_cb, pairwise floor 0.064 -- and it clears the OLD
                         all-arms floor (0.113) too, so this verdict does not lean on the
                         rule change. Closes 73.8% of the span between the unadapted
                         carrier and held-out Hemingway itself; lv-bronte closed 48%.
  B. NOT COPIED  see below
  C. NO DAMAGE   PASS    ran-on +0.08, on-beat -0.14, both inside a 0.217 floor

AXIS B: THE NEGATIVE CONTROL WAS THE WRONG ONE, AND FIXING IT MADE THE RESULT WORSE, NOT
BETTER. memorization_check.py uses the base-unadapted arm as its control. Base writes
18,035 words of summary against the adapted arms' 27,413 of pastiche, and text that does
not imitate a register cannot collide with its n-grams -- so base's 0.00 measures "different
register", not "did not memorise". The comfortable reading was that Hemingway's plain
high-frequency prose makes collisions inevitable for any arm that learns it. That is
refutable, so it was tested: held-out Hemingway, the author himself, scored against the
train split at the generations' own median length.

  HELD-OUT HEMINGWAY (never trained)   370 chunks   0.01 hit-rate   mean-longest 0.1   max 10
  base-unadapted                       240 gens     0.00                        0.0        0
  ckpt850 (shipped)                    240 gens     0.07                        0.6        9
  positive control (train vs train)                                             160

The hypothesis is false: the adapter reproduces train n-grams ~7x more often than the
author reproduces himself. That is real and is on the record. All 19 matched runs were then
READ rather than counted -- every one is stock dialogue ("came over and sat down at the
table", "how do you feel i feel very well"), capped at 9 words, with no plot, no imagery and
no proper noun; the one name-shaped hit is the RENAMED invented name. Nine is shorter than
the 10-word run unseen Hemingway shares with the train split by coincidence. Elevated rate,
zero protectable content. Hemingway is in copyright; lv-yarros is the in-line precedent,
also in copyright, shipped at 0.10 against a 0.07 control. Unload is 0.003 s.

The durable lesson is about the instrument: a negative control that differs from the
candidate in a way correlated with the metric is not a control. memorization_selfsim.py and
memorization_dump_matches.py are committed so the claim can be re-derived rather than taken
on faith.

SHIPPED ckpt850, NOT the loss minimum at step 1750. The two are indistinguishable on voice
-- 0.072 apart against a 0.113 pairwise floor -- so the pre-registered tiebreak fell to the
axes that resolve, and 850 wins all of them: 2.3x tighter seed spread (0.050 vs 0.113),
lower memorisation, less ran-on, half an epoch less overfit. ckpt1750's spread is one seed
(0.491, 0.449, 0.468, then 0.562), the same lone-outlier shape that lost ckpt925 the
lv-bronte tiebreak. The two-epoch recipe is now 0 for 2 and should stop being carried
forward; only the epoch-3 collapse is robust at 17.4x jitter.

servers/fv-ml1/ssh-target was a bare IP, so deploy-stack.sh connected as lkraven, could not
write the infra-ops-owned /opt/docker/compose, and could not escalate either because
lkraven's sudo on fv-ml1 wants a password. Now infra-ops@10.251.50.54; --validate-only stays
clean and the deploy works through the repo's own tool rather than around it. Other hosts
may carry the same gap -- a read-only refresh works as either user, so it only surfaces on a
deploy.

scripts/hemingway-corpus/eval-hemingway.sh

@@ -0,0 +1,82 @@
+#!/bin/bash
+# lv-hemingway v2 gate. Design is FROZEN in scripts/hemingway-corpus/GATE-PREREG.md
+# and was written before this script ever ran. Do not edit the arms, the fixture
+# size or the seeds to chase a result -- re-run, do not re-tune.
+#
+# THREE ARMS. ckpt1750 is the eval-loss minimum (2.2783, epoch 1.973). ckpt850
+# (2.2823, epoch 0.959) is +0.0040 against a 0.0044 median neighbour jitter, i.e.
+# TIED -- the loss curve cannot pick between them, and on Bronte the earlier
+# epoch-1 checkpoint won the tiebreak on the axes that do resolve. `base` is the
+# negative control for memorisation (it never saw the corpus) and the voice
+# baseline. adapter/ (epoch 3.0, +0.0762 = 17.4x jitter) is NOT gated: that one
+# the loss curve settles on its own.
+set -o pipefail
+cd ~/lv-hemingway || exit 1
+PY=/home/infra-ops/ml/.venv/bin/python
+RUN=~/r49-runs/hemingway-4b-pairs-3ep
+OUT=~/r49-runs/hemingway-eval
+BEATS=beats-hemingway-60.json
+PROV=pairs/pairs-full.jsonl.provenance.json
+SEEDS="1234 5678 9012 3456"
+mkdir -p "$OUT"
+log(){ echo "[eval $(date +%H:%M:%S)] $*"; }
+
+# --system-from is MANDATORY. The harness's built-in SYS is Yarros's; driving a
+# Hemingway arm with it would confound the adapter change with a prompt change.
+# This binds the eval prompt to the one the run actually trained under (verified:
+# run provenance system_prompt == pairs provenance system_prompt).
+[ -f "$PROV" ] || { log "MISSING $PROV"; exit 1; }
+[ -f "$BEATS" ] || { log "MISSING $BEATS"; exit 1; }
+
+for arm in base:NONE ckpt1750:$RUN/checkpoints/checkpoint-1750 ckpt850:$RUN/checkpoints/checkpoint-850; do
+  name=${arm%%:*}; path=${arm#*:}
+  if [ "$name" != "base" ] && [ ! -d "$path" ]; then log "MISSING $path"; exit 1; fi
+  if [ -s "$OUT/beats5.$name.jsonl" ]; then
+    log "arm $name already has $(wc -l < "$OUT/beats5.$name.jsonl") generations -- skipping"
+    continue
+  fi
+  log "arm $name"
+  if [ "$name" = "base" ]; then
+    "$PY" scripts/r49-corpus/gen_beats_chat_yarros.py \
+      --base ~/carriers/Qwen3-4B-Instruct --beats "$BEATS" \
+      --out "$OUT/beats5.$name.jsonl" --arm "$name" --seeds $SEEDS \
+      --system-from "$PROV" || exit 1
+  else
+    "$PY" scripts/r49-corpus/gen_beats_chat_yarros.py \
+      --base ~/carriers/Qwen3-4B-Instruct --adapter "$path" --beats "$BEATS" \
+      --out "$OUT/beats5.$name.jsonl" --arm "$name" --seeds $SEEDS \
+      --system-from "$PROV" || exit 1
+  fi
+  log "  $(wc -l < "$OUT/beats5.$name.jsonl") generations"
+done
+
+log "AXIS B -- MEMORISATION (corpus = the renamed copies the adapter trained on)"
+# --corpus and --eval-dir are passed explicitly: the script's Yarros defaults would
+# compare a Hemingway arm against the YARROS corpus and report a clean zero that
+# means "different book", not "did not memorise".
+"$PY" scripts/yarros-corpus/memorization_check.py \
+  --eval-dir "$OUT" --corpus corpus-renamed/copies --glob 'beats5.*.jsonl' --strip 'beats5.' -n 8 \
+  2>&1 | tee "$OUT/memorization.txt"
+
+log "AXIS C -- DAMAGE (ran-on / out-of-band), ckpt1750 vs base"
+"$PY" scripts/yarros-corpus/score_beats.py \
+  --arm base="$OUT/beats5.base.jsonl" \
+  --arm ckpt1750="$OUT/beats5.ckpt1750.jsonl" \
+  --arm ckpt850="$OUT/beats5.ckpt850.jsonl" \
+  --baseline base --candidate ckpt1750 --metric-source raw \
+  --out "$OUT/score.ckpt1750.json" 2>&1 | tee "$OUT/score.ckpt1750.txt"
+log "AXIS C -- DAMAGE, ckpt850 vs base"
+"$PY" scripts/yarros-corpus/score_beats.py \
+  --arm base="$OUT/beats5.base.jsonl" \
+  --arm ckpt1750="$OUT/beats5.ckpt1750.jsonl" \
+  --arm ckpt850="$OUT/beats5.ckpt850.jsonl" \
+  --baseline base --candidate ckpt850 --metric-source raw \
+  --out "$OUT/score.ckpt850.json" 2>&1 | tee "$OUT/score.ckpt850.txt"
+
+log "AXIS A -- VOICE (delta_cb vs held-out Hemingway)"
+"$PY" voice-prep.py || exit 1
+"$PY" scripts/r49-corpus/voice_distance.py corpus-renamed "$OUT" --author Hemingway \
+  2>&1 | tee "$OUT/voice_distance.txt"
+
+echo "rc=0" > ~/lv-hemingway/.eval-complete
+log "done"

scripts/hemingway-corpus/voice-prep.py

@@ -0,0 +1,47 @@
+"""Adapt the lv-hemingway arms for voice_distance.py, and refuse if its reference is empty.
+
+voice_distance.py expects:
+  - files matching voice.<arm>.jsonl in the eval dir
+  - a `continuation` field per record (gen_beats_chat writes `raw`)
+  - a `seed` field (present)
+  - the control arm's NAME to contain the substring "unadapted" -- it picks the
+    control by that substring, so `base` alone would leave the control
+    unidentified and the whole vs-control table would silently be empty.
+  - a reference built from corpus records whose split == "val"
+"""
+import json, sys
+from collections import Counter
+from pathlib import Path
+
+CORP = Path("/home/infra-ops/lv-hemingway/corpus-renamed/copies")
+EVAL = Path("/home/infra-ops/r49-runs/hemingway-eval")
+
+c = Counter()
+n = 0
+for p in sorted(CORP.glob("*.jsonl")):
+    for line in p.read_text(encoding="utf-8").splitlines():
+        if not line.strip():
+            continue
+        r = json.loads(line)
+        n += 1
+        c[r.get("split")] += 1
+print(f"corpus records: {n}  split values: {dict(c)}")
+if c.get("val", 0) == 0:
+    print("== REFUSING: no split=val records; voice_distance would build an EMPTY reference")
+    print("   and every delta_cb would be meaningless rather than absent.")
+    sys.exit(1)
+
+NAMES = {"base": "base-unadapted", "ckpt1750": "ckpt1750", "ckpt850": "ckpt850"}
+for src_arm, out_arm in NAMES.items():
+    src = EVAL / f"beats5.{src_arm}.jsonl"
+    if not src.exists():
+        print(f"== missing {src}")
+        sys.exit(1)
+    rows = [json.loads(l) for l in src.read_text(encoding="utf-8").splitlines() if l.strip()]
+    out = EVAL / f"voice.{out_arm}.jsonl"
+    with out.open("w", encoding="utf-8") as fh:
+        for r in rows:
+            fh.write(json.dumps({"id": r["id"], "seed": r["seed"],
+                                 "continuation": r["raw"]}, ensure_ascii=False) + "\n")
+    print(f"  {src.name} -> {out.name}  ({len(rows)} records)")
+print("ready")