feat(litellm): Worldtree capability aliases (chat-judge, reranker, scalar-judge)

Stand up the gateway-side capability aliases for the role→capability model
indirection (worldtree-dev's transparent-swap direction; operator: no wt-
prefix, reuse the existing summarizer/classifier/gen alias convention).

- chat-judge  -> selene-1-mini-8b (mode chat)  — WT selene-judgment role.
- reranker    -> qwen3-reranker (mode rerank)  — generic name for the cap.
- scalar-judge -> Skywork-Reward-V2 via a pass_through_endpoint to ana-ml2:8003
  (LiteLLM has no reward/pooling MODE, so it's a passthrough, gateway-key-gated;
  consumers hit /scalar-judge/<route> e.g. /score|/pooling|/classify).

Deliberately NO generic `embedding` alias: embedding vectors are model-specific
(not swap-transparent), so that capability stays `qwen3-embedding` — the model-
specific name is the guardrail against treating it as freely swappable. Verified
all three live (chat-judge 200, reranker present, scalar-judge passthrough 200
returning a Skywork reward). Deployed + gateway health-gated.

stacks/litellm/conf/config.yaml

@@ -189,6 +189,28 @@ model_list:
     model_info:
       mode: rerank
 
+  # --- Worldtree capability aliases (role→capability gateway swaps, ADR-0012).
+  #     Stable role-named aliases so consumers bind the CAPABILITY, not a concrete
+  #     model; swap the backing model here and callers are unaffected. NO generic
+  #     `embedding` alias ON PURPOSE — embedding vectors are model-specific (not
+  #     swap-transparent), so that capability stays `qwen3-embedding` above. ---
+  # chat-judge → generative LLM-as-judge (Selene); WT selene-judgment role.
+  - model_name: chat-judge
+    litellm_params:
+      model: hosted_vllm/selene-1-mini-8b
+      api_base: http://10.250.50.54:8011/v1
+      api_key: os.environ/VLLM_API_KEY
+    model_info:
+      mode: chat
+  # reranker → generic capability name for rerank (currently qwen3-reranker).
+  - model_name: 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
+
   # --- z.ai GLM (cloud API) — fronted for unified logging across local
   #     + cloud inference. Explicit entries, so they win over the "*"
   #     wildcard below (no collision with llama-swap's glm4.7-flash etc.
@@ -276,6 +298,17 @@ general_settings:
   # SpendLogs so they render in the Logs UI. Without this you get metadata
   # (tokens, latency, model) but not the prompt/completion text.
   store_prompts_in_spend_logs: true
+  # scalar-judge → Skywork-Reward-V2 (scalar reward model; vLLM pooling on
+  #   ana-ml2:8003). LiteLLM has no reward/pooling MODE, so this is a passthrough,
+  #   not a model_list alias. Gateway-key-gated. Consumers POST the reward body to
+  #   /scalar-judge/<route> (e.g. /pooling or /classify), forwarded to :8003.
+  #   SWAP-SENSITIVE: a different reward model shifts the score scale, so consumers
+  #   must recalibrate thresholds after a backing swap.
+  pass_through_endpoints:
+    - path: "/scalar-judge"
+      target: "http://10.250.50.54:8003"
+      forward_headers: true
+      include_subpath: true
 
 litellm_settings:
   # vLLM rejects some OpenAI params other backends accept; drop silently