observability: the LLM surfaces follow the two-endpoint split

frank-large has no /metrics to scrape any more, and scraping it would be red by
construction: the halogen engine publishes /health, /cache and /v1/* only. That
job is removed with the reason written down (the remedy is the blackbox
exporter this fleet already wants for the comfyui/services probes), and
frank-small's llama.cpp endpoint takes the slot at 192.168.0.143:7771.

Homepage: frank-large's card still described the ik runtime, and the new
endpoint had no card at all. Both fixed, with a loopback probe -- the checker
runs on Dankclaw, which is also what makes the card green-able.

Dashboard: the endpoint picker was sourced from a vLLM-only metric, so a
llama.cpp job could never be selected, and the prose named frank-large as the
llama.cpp endpoint. The picker now matches both runtimes' series and the
llama.cpp targets carry the job filter every other panel already used.

The seams assert the new contract including the ABSENCE of a 7770 target, so a
well-meaning edit cannot re-add a permanently-red probe.

shared/prometheus/prometheus.yml

@@ -68,7 +68,15 @@ scrape_configs:
   # and the prefix-cache pair vllm:prefix_cache_hits_total over
   # vllm:prefix_cache_queries_total (their rates give the hit rate, which says
   # whether pinned conversations are actually being reused).
-  # frank-large is llama.cpp and exposes throughput counters under llamacpp:.
+  # frank-large is deliberately NOT scraped: the halogen engine that serves it
+  # publishes /health, /cache and /v1/* and no Prometheus text endpoint, so a
+  # target here would be red by construction and would fire LlmEndpointDown
+  # forever. Its liveness is on the homepage (a loopback probe) and in the
+  # engine's own boot ledger. The remedy, when the fleet wants it, is the
+  # blackbox exporter already wanted for the comfyui/services probes.
+  #
+  # frank-small is llama.cpp (its serve script passes --metrics) and does
+  # export text-format counters under llamacpp: on the port its unit publishes.
   - job_name: "frank-medium"
     metrics_path: "/metrics"
     static_configs:
@@ -76,9 +84,9 @@ scrape_configs:
         labels:
           service: frank-medium
 
-  - job_name: "frank-large"
+  - job_name: "frank-small"
     metrics_path: "/metrics"
     static_configs:
-      - targets: ["192.168.0.143:7770"]
+      - targets: ["192.168.0.143:7771"]
         labels:
-          service: frank-large
+          service: frank-small