feat(monitoring,harness): follow frank-medium onto vllm:* metrics and fix red-by-construction targets

The radiance TP=2 cutover changed the metric namespace frank-medium exports
(llamacpp:* -> vllm:*) and left two scrape targets addressing host processes
by an address a container cannot reach.

- shared/prometheus/rules/llm-fleet.yml: two namespaces side by side. Added
  LlmRequestsWaiting, LlmKvCacheSaturated (vllm-only gauges llama.cpp never
  had), the job:llm_vllm_prefix_cache_reuse:rate5m and
  job:llm_spec_accept_length:rate5m recording rules, and re-cut
  LlmPrefixCacheCollapse / LlmSpecDecodeOff to OR both families with
  per-family traffic floors so an idle endpoint cannot fire them. Every
  expression validated against live Prometheus.
- shared/prometheus/prometheus.yml: frank-small -> host.containers.internal:7771
  and frank-large scraped at host.containers.internal:7770. Both are HOST
  processes on Dankclaw and netavark DNATs published container ports only, so
  the LAN-IP targets were red by construction; frank-large's CIRU llama.cpp
  build does export the llamacpp:* family, contra the old comment.
- tests/observability_quadlet.bats: the two seams now encode the new contract
  (per-endpoint reachability by process type; every named series must be on the
  measured list for its engine; engine-independent rules must name both).
- homepage docs.html/services.json: frank-medium sees pictures, frank-large is
  CIRU Orca with a single seat (was halogen w4b, two seats, 200k).
- docs: radiance runbook is ACTIVE (deployed flags, three-arm battery, verified
  capabilities, rollback, replica-era sections labelled); llama.cpp runbook
  carries the SUPERSEDED banner; Dual-R9700-Cooperation states the measured
  verdict; Observability records the namespace split and the DNAT lesson;
  AGENTS.md topology/frank-medium/Model Config/Benchmarking Policy/runbook
  index flipped; both indexes updated; work-log entry added.

Also repaired agent-pass damage: prose prepended above frontmatter openers,
duplicated runbook bodies, a literal tool-call token pasted into a runbook, and
an index destroyed by diff artifacts (restored from HEAD, flips re-applied).
Vault link check: 128 pages, 0 unresolved. ./tests/run.sh: 325 pass.

shared/homepage/services.json

@@ -233,7 +233,7 @@
   {
     "name": "frank-large",
     "category": "user",
-    "description": "The big brain. Qwen3.8-Flash-Next w4b on halogen-flash-server, running on Dankclaw's Strix Halo iGPU. Text-only; holds two 200k-token conversations resident.",
+    "description": "The big brain. Qwen3.8-Flash CIRU-STRIX-Orca on CIRU v4.4.1 llama.cpp, running on Dankclaw's Strix Halo iGPU. Text-only; one conversation resident at a time.",
     "url": "",
     "docs": "/docs#models",
     "probe": "127.0.0.1:7770",