docs(vault): audit tranche 1 — one-owner dedupe of the observability cluster, dead-shape numbers destroyed

Purpose-test pass over the audit findings (every verdict re-verified
against the file before touching it; three scout findings were hallucinated
— a nonexistent filename, my own changelog line, and sanctioned Eras rows):

- Observability Provisioning: destroyed the 63-line 'Current delivered
  state' block — chain topology/relay/delivery restates [[Observability]]
  and [[Alertmanager]] (those are the owners). Its three sole-custody laws
  MOVED to Stale Signal Audit as 'Three rules that outlive the incident':
  down-beside-healthy -> read lastError; Prometheus alert state in process
  vs Alertmanager's --storage.path persistence; candidate-arm metrics are
  never fleet state.
- RDNA4 MoE VRAM budget: kept the laws (registry over-prices the pool;
  never reuse a B/token ratio across geometries; pin pool bytes
  floor-sized), era-labelled the rates, destroyed the measured ladder
  table for the superseded shape-G/bf16 rungs.
- Stale Signal Audit: new rules section + Provisioning Related link.

check-okf 109/0, vault links 0 unresolved, docs seams green.

serverAppConfigs-docs/Architecture/Stale Signal Audit.md

@@ -116,6 +116,20 @@ as working when they could never report up. **Clean cutover includes prose** —
 docs, unit docstrings, and the repo's rule file (the most expensive place to
 be stale).
 
+## Three rules that outlive the incident that taught them
+
+* **A target can read down beside a healthy service.** Read `lastError` from
+  `/api/v1/targets` before believing an outage — llama.cpp refuses `/metrics` at the
+  protocol layer without `--metrics` (501) while `/health` answers 200 for weeks.
+* **Alert state lives where the tool says it does.** Prometheus keeps rule state in
+  process memory — a restart re-stamps `activeAt`, so a "fresh" alert after a reboot is
+  not evidence of a fresh fault. Alertmanager **does** persist (`--storage.path` on a
+  host volume: silences + notification log, [[Alertmanager]]).
+* **Never quote a candidate arm's flags or VRAM as fleet state.** A stopped production
+  unit (`failed` after `stop-sigterm timed out. Killing` — the known shutdown shape,
+  [[frank-zealot]]) beside an answering port means the metric measured a scratch boot;
+  the process shape can change between two censuses ten minutes apart.
+
 ## Order and verification
 
 1. Enumerate the surfaces (status board, metrics targets, alert rules, test