retire frank-medium: tests, planning and observability ground on frank-primary

The frank-medium retirement tail the 2026-09-26 lucebox cutover left
uncommitted: the radiance quadlet tree, its swap/fetch tooling and its
seam test are deleted (archive copies live in dankserver/.AGENTTRASH/
20260926-frank-medium-radiance/ and scripts/.AGENTTRASH/20260926-
frank-medium-radiance/), the planner/allowlist/test-changed mappings
drop the service, and frank-large's chat template moves to scripts/
(its old home was the retired frank-medium dir).

Finished here:
- tests/frank_primary_unit.bats: the lucebox quadlet seam (boot
  persistence, host-network bind, HIP_VISIBLE_DEVICES=0,1, HIP-reserved
  env-name guard, checkout-mounted entrypoint/healthcheck, first-start
  patience, deployer payload/port gates).
- test-changed.sh: explicit .AGENTTRASH/ case — retirement commits move
  files to trash, and the wrapper refused those additions with "no
  focused-test mapping".
- observability: the vllm: namespace left with the radiance runtime.
  Rules keep only llamacpp:* series (prefix-cache reuse, spec-decode,
  queueing, endpoint-down); the dashboard drops the vLLM KV/latency
  panels; prometheus.yml documents that frank-primary (lucebox) has no
  /metrics and therefore no scrape job. llm-fleet.json was left
  corrupted mid-edit (missing opening brace) and is rewritten from HEAD.

Suite: 339 green (was 7 red).

shared/prometheus/prometheus.yml

@@ -79,19 +79,11 @@ scrape_configs:
   # this container, not the guarded vhosts: these are machine clients and
   # Prometheus cannot solve an Anubis challenge.
   #
-  # Two metric namespaces, because the fleet runs two runtimes:
-  #
-  #   * vllm:* — frank-medium (vllm-radiance TP=2 since 2026-09-20): prompt and
-  #     generation token counters, num_requests_waiting plus its reason label,
-  #     num_preemptions_total, the kv_cache_usage_perc fill gauge, the
-  #     prefix_cache hits/queries pair, the spec_decode drafts/accepted triple,
-  #     and real latency histograms (time_to_first_token, inter_token,
-  #     e2e_request_latency).
-  #   * llamacpp:* — frank-large and frank-small. Both take --metrics and both
-  #     were verified 2026-09-20 to export requests_deferred (the queue depth,
-  #     the only form llama.cpp shows the capacity wall in),
-  #     spec_decode_num_drafts_total, tokens_predicted_total, and the
-  #     prompt_tokens_cached_total / prompt_tokens_total reuse pair.
+  # One metric namespace: llamacpp:* — frank-large and frank-small, both
+  # llama.cpp with --metrics and both verified 2026-09-20 to export
+  # requests_deferred (the queue depth, the only form llama.cpp shows the
+  # capacity wall in), spec_decode_num_drafts_total, tokens_predicted_total,
+  # and the prompt_tokens_cached_total / prompt_tokens_total reuse pair.
   #
   # frank-large is scraped over host.containers.internal, not its own LAN address:
   # this Prometheus is a bridge-networked container (Network=dankclaw_default),
@@ -102,14 +94,10 @@ scrape_configs:
   # "dial tcp 192.168.0.143:7771") even though the endpoint was healthy and
   # exporting: the target address was unreachable by construction, not the
   # service down. Same host, same rule, so both local endpoints use the gateway.
-  # frank-medium stays a LAN address — it is a different machine.
-  - job_name: "frank-medium"
-    metrics_path: "/metrics"
-    static_configs:
-      - targets: ["192.168.0.235:7770"]
-        labels:
-          service: frank-medium
-  
+  # (2026-09-26) frank-medium is replaced by frank-primary (lucebox DS4.1),
+  # which exposes no metrics endpoint (/metrics -> 404), so there is no job
+  # for it here. The endpoint's liveness is covered by the homepage probe;
+  # the documented remedy is a blackbox exporter, which is not deployed.
   - job_name: "frank-small"
     metrics_path: "/metrics"
     static_configs: