monitoring: add quarterly UPS self-test script (Phase 4B)

ups-quarterly-test.sh:
  - Runs test.battery.start.quick on cyberpower1 then cyberpower2
  - 120s wait between tests (allow recharge)
  - Logs pass/fail to syslog via logger -t ups-quarterly-test
  - Password stored in single-quoted variable to prevent shell expansion
  - Deployed on beast (/usr/local/bin/), cron: first Sunday of Jan/Apr/Jul/Oct 02:00

Manual run 2026-05-06:
  cyberpower1: Done and passed (charge 97% post-test, recharged normally)
  cyberpower2: Done and passed (charge 100%)

Grafana alerts (in grafana.db):
  cfl8lrs1mxnnka  UPS Battery Charge Low (<80%) — break-tested pending ✓
  afl8lrs4mbaioa  UPS On Battery (power outage) — break-tested fired ✓

Note: nut_battery_test_result not exposed by nut-exporter v1.2.1.
Pass/fail tracked via syslog only for now. Adding to Phase 5 if exporter
gains test-result metric support.

monitoring/ups-quarterly-test.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+# Quarterly UPS battery self-test — runs via cron first Sunday of Jan/Apr/Jul/Oct
+NUT_PASS='Sparky$100'
+NUT_USER='upsadmin'
+NUT_HOST='localhost'
+
+logger -t ups-quarterly-test 'starting quarterly battery self-test'
+
+logger -t ups-quarterly-test 'testing cyberpower1 (Tower)'
+upscmd -u "$NUT_USER" -p "$NUT_PASS" cyberpower1@$NUT_HOST test.battery.start.quick 2>&1 |   logger -t ups-quarterly-test
+
+sleep 120
+
+result1=$(upsc cyberpower1@$NUT_HOST ups.test.result 2>/dev/null)
+logger -t ups-quarterly-test "cyberpower1 result: $result1"
+
+logger -t ups-quarterly-test 'testing cyberpower2 (Rackmount)'
+upscmd -u "$NUT_USER" -p "$NUT_PASS" cyberpower2@$NUT_HOST test.battery.start.quick 2>&1 |   logger -t ups-quarterly-test
+
+sleep 120
+
+result2=$(upsc cyberpower2@$NUT_HOST ups.test.result 2>/dev/null)
+logger -t ups-quarterly-test "cyberpower2 result: $result2"
+
+if [[ "$result1" == 'Done and passed' && "$result2" == 'Done and passed' ]]; then
+    logger -t ups-quarterly-test 'PASS: both UPS batteries healthy'
+else
+    logger -t ups-quarterly-test 'FAIL: one or more UPS batteries need attention'
+fi