feat(embed-rerank): TEI is the fleet embed/rerank engine; esh-ml1 sole backend; retire fv-ml1 seats

Prime, 2026-09-25: TEI serves embedding + reranking for esh-ml1 and the fleet
from now on; fv-ml1 retires both once esh-ml1 is up.

- stacks/embed-rerank: vLLM -> TEI 1.9.4 (89- Ada build), same ports
  8001/8013, fail-closed truncation (--auto-truncate false; embed
  --max-batch-tokens 32768).
- litellm: qwen3-embedding -> esh-ml1 only (hosted_vllm/, unchanged address);
  reranker -> huggingface/ provider at :8013 (hosted_vllm/ 422s on TEI's
  `texts` body). DB alias reranker-a3-bge-v2-m3 patched to the same target.
- Verified via the gateway against the retiring fv-ml1 seats: embed cosine
  median 0.999927 (n=203); rerank top-1/top-3 29/30.
- stacks/vllm: vllm-embed and vllm-rerank-a3 removed (containers retired on
  fv-ml1, GPU 1 freed ~6.1 GB); reward + coder unchanged.
- Bake-off record moved to docs/pfi/embed-rerank-tei-vs-vllm-bakeoff.md;
  CLAUDE.md gains the TEI convention.

docs/fleettools/litellm.md

@@ -33,8 +33,8 @@ on someone else's tab" matters, get a project-scoped key.
 `summarizer` / `summarizer-large` / `classifier` — the always-available local seat for
 summarization, naming/labeling, classification and triage. Essentially free compute;
 reach for it before spending premium API tokens on work a small local model handles.
-Embeddings and rerankers (`qwen3-embedding`, `qwen3-reranker`, `reranker`) are local
-and free too. Anything named `*-frontier`, `glm-*` or `kimi-*` is **PAID**.
+Embeddings and reranking (`qwen3-embedding`, `reranker`) are local and free too —
+served by TEI on esh-ml1 since 2026-09-25 (`qwen3-reranker` was retired 2026-08-20). Anything named `*-frontier`, `glm-*` or `kimi-*` is **PAID**.
 
 ## Traps