fix(nevermore): repoint onto live aliases — its LLM pass had been dead 8 days

nevermore pinned LLAMA_SWAP_MODEL=granite-4.1-8b, an alias retired with the
granite seat on 2026-08-12. Every summarization call since then failed: 67
consecutive status=failure rows, 0 tokens, twice daily, entirely silently. The
briefing had been rendering with no LLM pass at all. Nothing alerts on
status=failure in the spend logs, so it took an unrelated question about
reranker VRAM to surface it.

It was also pinned to NEVERMORE_RERANK_MODEL=qwen3-reranker -- the incumbent
Brokkr R43 measured harming 80/90 fleet queries -- and was its ONLY caller,
while the production `reranker` alias sat at 0 calls for 4 days. The R43
cutover repointed the alias but never moved the consumer.

  nevermore/.env  LLAMA_SWAP_MODEL       granite-4.1-8b -> summarizer
                  NEVERMORE_RERANK_MODEL qwen3-reranker -> reranker
                  (server-only; .env is excluded from the mirror both ways)

Verified against nevermore's exact call shape: summarizer returns clean content
with 0 reasoning chars at temperature 0.2 / max_tokens 4000; reranker scores
0.95 on-topic vs ~1e-5 off-topic; embedding returns dim-1024.

Retired alongside it:

  vllm-rerank    :8002  Qwen3-Reranker-0.6B + the qwen3-reranker alias
  vllm-rerank-a4 :8014  gte-reranker-modernbert + its alias
  vllm-granite   :8004  Exited 8 days, dead service block

and vllm-rerank-a3 was promoted from a throwaway `docker run` into this stack
(the selection ledger's own open follow-up). Healthy in 55s. It keeps the
bake-off arm name so the ledger, memory and R43 record stay valid.

VLLM_VERSION is pinned latest -> v0.24.0. Every service in the stack shares that
one variable, so a bare `compose up -d` could have silently upgraded all of
them at once; both tags resolved to the same local image (4091d5593f77), so the
pin changed nothing at runtime.

GPU1 is down to 81,448 of 97,887 MiB -- 13.9 GB reclaimed tonight.

Correction: an earlier claim that A4 had no gateway alias was wrong. It did.
LiteLLM serves both config-defined and DB-defined models -- live showed 32
against config.yaml's 26 -- and grepping the file cannot see the difference.
/v1/models and /model/info (which flags db_model) are the ground truth. DB
models delete hot via POST /model/delete with no restart.

Left alone: reranker-a3-bge-v2-m3, a zero-call duplicate of `reranker` on the
same backend. It is Brokkr's cutover-verification handle -- redundant rather
than broken, and another agent's tooling is not mine to delete unilaterally.

stacks/litellm/conf/config.yaml

@@ -8,7 +8,8 @@
 # Model-name → upstream mapping:
 #   phi4-mini        → vLLM :8004  (generative chat)
 #   qwen3-embedding  → vLLM :8001  (/v1/embeddings)
-#   qwen3-reranker   → vLLM :8002  (/rerank)
+#   reranker         → vLLM :8013  (/rerank; bge-v2-m3. The old qwen3-reranker
+#                                   alias on :8002 was retired 2026-08-20.)
 #   *  (wildcard)    → llama-swap :9292  (the swappable generative zoo)
 #
 # The wildcard fronts llama-swap so its whole model zoo logs through the
@@ -313,14 +314,14 @@ model_list:
     model_info:
       mode: embedding
 
-  # --- Qwen3 reranker (proxy /rerank route) ---
-  - model_name: qwen3-reranker
-    litellm_params:
-      model: hosted_vllm/Qwen/Qwen3-Reranker-0.6B
-      api_base: http://10.250.50.54:8002/v1
-      api_key: os.environ/VLLM_API_KEY
-    model_info:
-      mode: rerank
+  # --- qwen3-reranker RETIRED 2026-08-20. It named Qwen3-Reranker-0.6B on :8002,
+  #     the incumbent the R43 bake-off replaced on 2026-08-06 after measuring it
+  #     HARMING 80/90 fleet queries (no-reranker beat it 89/90 vs 56/90). The alias
+  #     was kept as the rollback path and, for 13 days, was the ONLY reranker
+  #     actually receiving traffic: nevermore was pinned to it by name, so the
+  #     cutover moved `reranker` but never moved nevermore. Fixed at the consumer
+  #     (nevermore now pins `reranker`), then the seat and this alias were retired.
+  #     Use `reranker` -> bge-reranker-v2-m3 :8013. ---
 
   # --- Worldtree capability aliases (role→capability gateway swaps, ADR-0012).
   #     Stable role-named aliases so consumers bind the CAPABILITY, not a concrete
@@ -337,7 +338,8 @@ model_list:
       top_p: 0.9
     model_info:
       mode: chat
-  # reranker → generic capability name for rerank (currently qwen3-reranker).
+  # reranker → generic capability name for rerank. THE reranker alias — the only
+  # one left as of 2026-08-20. Every consumer pins this name, never a model name.
   - model_name: reranker
     litellm_params:
       model: hosted_vllm/BAAI/bge-reranker-v2-m3