fix(frank-zealot): serve /metrics so Prometheus can see the endpoint

The scrape has never worked: lastError is "server returned HTTP status 501 Not
Implemented" on http://host.containers.internal:7771/metrics, and the oldest
retained sample of up{job="frank-zealot"} (2026-10-11) is already 0 -- the target
has been red across four payload generations while /health answered 200 the whole
time, keeping the critical LlmEndpointDown alert permanently active. llama.cpp
gates /metrics behind --metrics; halogen serves it natively, which is why the
asymmetry looked like a 3090-only problem.

METRICS=1 in the shipped env, --metrics reaches the argv through EXTRA_ARGS, and
the seam asserts both directions (default ships the flag, METRICS=0 strips it).
Diagnosed via /api/v1/targets lastError rather than the alert list, which is also
the lesson: Alertmanager here has no persistence, so a reboot re-stamps startsAt
and a weeks-old fault looks fresh.

scripts/frank-zealot.env

@@ -70,3 +70,12 @@ NGL=99
 # and graph capture land in the journal, which is what the VRAM-fit forensics
 # read. Levels above 4 flood the journal.
 VERBOSITY=4
+
+# Serve /metrics. llama.cpp answers 501 without --metrics, and Dankclaw's
+# Prometheus scrapes /metrics on every fleet endpoint — a 501 reads as DOWN, so
+# this service has held the critical LlmEndpointDown alert for as long as the
+# metric has history (verified 2026-10-18: the oldest retained sample of
+# up{job="frank-zealot"}, 2026-10-11, is already 0; scrapeUrl
+# http://host.containers.internal:7771/metrics, lastError "server returned HTTP
+# status 501 Not Implemented"). 0 opts out and re-breaks the scrape.
+METRICS=1

scripts/serve-frank-zealot.sh

@@ -78,6 +78,15 @@ fi
 # 4 adds debug detail (KV layout, buffer sizes, graph capture) which is what
 # the VRAM-fit forensics need. Levels above 4 flood the journal.
 : "${VERBOSITY:=3}"
+# /metrics needs the flag: llama.cpp returns 501 unless the server starts with
+# --metrics, and Dankclaw's Prometheus scrapes every fleet endpoint's /metrics —
+# a 501 reads as DOWN, which is how the critical LlmEndpointDown alert ended up
+# firing for this service ever since the metric has history at all — the oldest
+# retained sample of up{job="frank-zealot"} (2026-10-11) is already 0, so this
+# target has never been scraped successfully, across every payload era. The
+# counters cost nothing on the request path;
+# METRICS=0 is the documented opt-out.
+: "${METRICS:=1}"
 # Vision projector. No colon on purpose: an explicitly empty value means
 # "text-only, on purpose" and must NOT be replaced by the default path.
 : "${MMPROJ_FILE=/home/dank/models/Bonsai2-PQ2_0/Ternary-Bonsai-2-27B-mmproj-Q8_0.gguf}"
@@ -94,6 +103,12 @@ if [[ -n "$MMPROJ_FILE" ]]; then
     EXTRA_ARGS+=(--mmproj "$MMPROJ_FILE")
 fi
 
+# Prometheus scraping is opt-IN in llama.cpp: without --metrics the server
+# answers 501 on /metrics, and the fleet scrape then reports the endpoint DOWN.
+if [[ "$METRICS" = "1" ]]; then
+    EXTRA_ARGS+=(--metrics)
+fi
+
 # Speculative flags move as a set: they reach the argv ONLY when a drafter
 # is named. SPEC_TYPE=none (the shipped contract) strips both — a no-spec
 # baseline must not carry half a spec pair.