docs: record the alerting rules and what they still cannot do

Both pages claimed there was no alerting; there are six rules now, so they say
which rules exist, that promtool and /api/v1/rules both confirm them, and — in
the same breath — that no rule reaches a person, because this stack has no
Alertmanager and no contact point. The dashboard's ALERTS panel is named as the
only place an alert becomes visible without opening Prometheus.

serverAppConfigs-docs/LLM/frank-medium-radiance-mxfp4.md

@@ -418,8 +418,16 @@ scraped — Prometheus has `frank-medium` and `frank-large` jobs
 (queue depth), `rate(vllm:prefix_cache_hits_total[5m]) /
  rate(vllm:prefix_cache_queries_total[5m])` (whether pinned conversations are
 served warm), and the request-latency histograms. See
-[[Observability on Dankclaw]]. There is still **no alerting** in this stack, so
-a saturated pool will not page anyone — it shows up on a graph after the fact.
+[[Observability on Dankclaw]], and one Grafana dashboard reads them
+(**LLM fleet — capacity and reuse**).
+
+Five rules watch this service (`shared/prometheus/rules/llm-fleet.yml`): pool
+saturation above 90 %, requests queueing for 10 minutes, prefix reuse collapsing
+below 20 % with traffic, the scrape target down, and p95 latency above 60 s —
+each threshold tied to a measurement on this page rather than to a guess. They
+evaluate and show up on the dashboard's **Alerts firing** panel, but **nothing
+is notified**: this stack has no Alertmanager, so an alert reaches a person only
+if that person is looking. That is the honest state of "alerting" here.
 
 ## Citations