k8s(llm-serving): client-facing Service for candle-vllm coder

Creates coder-predictor selecting app=candle-vllm on ports 80 and 8080, so
clients keep one stable host name across the vLLM -> candle-vllm handoff and
only this selector changes from now on.

The retired KTML predictor requested two V100s and never reached Ready.

k8s/apps/llm-serving/coder-service.yaml

@@ -0,0 +1,40 @@
+# Stable client-facing name for the coder chat model, deliberately decoupled
+# from the process that serves it.
+#
+# poimen-memory addresses a Service, not a pod and not an InferenceService. The
+# vLLM -> candle-vllm handoff therefore changes this file's selector and nothing
+# else, so the client config never changes again and there is no window in which
+# the host name is wrong.
+#
+# The previous KTML predictor requested two V100s and never reached Ready, so it
+# held half the GPU pool while serving nothing. candle-vllm replaces it.
+#
+# Two ports on purpose:
+#   - 80    matches every other predictor Service in this namespace, and matches
+#           a client base URL that carries no port number.
+#   - 8080  is the container port. Publishing it directly avoids a port
+#           translation that is easy to get wrong in a curl.
+#
+# Do not delete and recreate this Service: a delete drops the ClusterIP, and a
+# client that cached the name during the gap fails until it re-resolves.
+apiVersion: v1
+kind: Service
+metadata:
+  name: coder-predictor
+  namespace: llm-serving
+  labels:
+    app.kubernetes.io/part-of: llm-serving
+    app: coder-predictor
+spec:
+  type: ClusterIP
+  selector:
+    app: candle-vllm
+  ports:
+    - name: http
+      protocol: TCP
+      port: 80
+      targetPort: 8080
+    - name: http-8080
+      protocol: TCP
+      port: 8080
+      targetPort: 8080

k8s/apps/llm-serving/kustomization.yaml

@@ -16,6 +16,7 @@ resources:
   - clef-serve.yaml
   # Stable client-facing name for the chat model. poimen-memory points at this Service,
   # so the vLLM -> candle-vllm handoff is a selector edit here and no client change.
+  - coder-service.yaml
   - reasoning-long-service.yaml
   # ornith is retired: its InferenceService still reports Ready=True while running zero
   # replicas, because desired equals available at 0. Its manifest was never committed,