fix(cyberprev-seat): serve coherent v2 quant from name-repaired source; wire gateway

The first cyberprev quant served pure gibberish despite passing every structural
check. Root cause: the hotdogs/Qwen3.8-27B-abliterated-cyber-preview checkpoint
ships broken -- 850 of 1199 tensors (the whole transformer body) carry a TRIPLED
`language_model.` prefix, confirmed present in the upstream HF index (an unsloth
export bug, not our download). transformers silently loaded the unmapped tensors
as random-init, the pipeline quantized noise, and structural verification passed
because it inspects the output config, never that input names mapped. A plain
greedy coherence smoke caught it; nothing structural could.

Fix: rewrite tensor names against a known-good reference of the same architecture
(qwen38-27b-uncensored-bf16), verified the repaired name-set == reference name-set
exactly (1199 tensors, 0 collisions), and re-quantized from the corrected source
(cyberprev-bf16-fixed). v2 is coherence-verified (spec off AND live with dflash):
Paris/Berlin/Rome, correct arithmetic precedence, primes, clean cyber-domain chat
with a proper thinking split. dflash k=7 measured at 2.77 mean acceptance length.

Seat serves cyberprev-27b / cyberprev-27b-thinking on :8025/GPU0 with dflash k=7,
displacing the retired sentinel-r3. Gateway: removed the retired sentinel-r3 /
sentinel-r3-reasoning aliases and added cyberprev-27b / cyberprev-reasoning -- NOT
repointed, since serving cyberprev weights under sentinel's name is silent
substitution. Verified end-to-end through the gateway; sentinel-r3 now 400s.

Playbook gains a superseded-claims row: structural verification does not imply a
good quant; a coherence smoke is the load-bearing gate, and third-party sources
must have their tensor names diffed against a reference before quantizing.

Broken v1 quant dir removed.

stacks/cyberprev-seat/compose.yaml

@@ -42,7 +42,7 @@ services:
       - "${CYBER_PORT:-8025}:8000"
     volumes:
       - /tank/aimodels/huggingface:/hfcache
-      - ${CYBER_MODEL:-/tank/aimodels/cyberprev-nvfp4-mixed}:/model:ro
+      - ${CYBER_MODEL:-/tank/aimodels/cyberprev-nvfp4-mixed-v2}:/model:ro
       # DFlash2 drafter, mounted unconditionally — inert if CYBER_SPEC_CONFIG selects an MTP
       # method, which does not reference /drafter. Shared with mog-sec and (formerly)
       # sentinel-r3: all three share the same 64-layer Qwen3.8-27B base and vocab, so one