monthly_maintenance: reschedule to 0 0 15 * * (15th at midnight)

Previously ran daily at 3am with internal self-gating. Now scheduled directly
on the 15th — uptime and interval gates still apply; a skip means next month's 15th.

Orchestrators/monthly_maintenance.sh

@@ -7,15 +7,14 @@
 #   1. Server uptime >= MONTHLY_UPTIME_THRESHOLD_DAYS days
 #   2. Last run was >= MONTHLY_RUN_INTERVAL_DAYS days ago (or never run)
 #
-# ── WHY UPTIME-TRIGGERED, NOT CRON ───────────────────────────────────────────────────────────
+# ── WHY UPTIME-GATED ─────────────────────────────────────────────────────────────────────────
 #   A scheduled reboot resets uptime. Monthly tasks (ZFS scrub, SMART long test) need a
 #   stable, settled system — not one that just rebooted. Uptime-gating ensures maintenance
 #   only runs after the server has been healthy for a full month, never immediately post-boot.
-#   The daily cron is just the trigger mechanism. The uptime and interval checks inside
-#   the script are what enforce the monthly cadence.
+#   If uptime or interval gate is not met on the 15th, the run is skipped until next month.
 #
 # ── HOW TO CALL ──────────────────────────────────────────────────────────────────────────────
-#   Cron: 0 3 * * * — daily 3am check. Script self-gates — calling it daily is safe.
+# Schedule: 0 0 15 * *  (15th of each month at midnight)
 #   Silent exit 0 when either gate is not met. Only outputs when maintenance actually fires.
 #
 # ── STATE FILE ────────────────────────────────────────────────────────────────────────────────
@@ -153,7 +152,7 @@ if [[ "$SHOW_STATUS" == true ]]; then
     fi
 
     echo ""
-    echo "  Schedule:   0 3 * * * (daily check — script self-gates)"
+    echo "  Schedule:   0 0 15 * * (15th of each month at midnight)"
     echo "  Force flag: --force bypasses both gates"
     echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
     exit 0

user_script_plug-in.sh

@@ -26,7 +26,7 @@
 #   sunday_morning_coffee_report.sh   7am Sunday    — full weekly digest
 #   weekly_health_digest.sh           8am daily     — profile-controlled health notification
 #   system_tuning_monitor.sh          every 6 hours — inotify + php-fpm trend tracking
-#   monthly_maintenance.sh            3am daily     — uptime-gated monthly tasks (self-gates to monthly)
+#   monthly_maintenance.sh            15th monthly  — uptime-gated heavy tasks (ZFS scrub, SMART long test)
 #
 # ── INDIVIDUAL SCRIPTS ────────────────────────────────────────────────────────────────────────
 # Every child script is also listed below, individually.
@@ -90,7 +90,7 @@
 #           before rsync_stop) — fallback runs as a bare subprocess, not via /tmp/user.scripts,
 #           so it is not caught by user_scripts_stop.sh.
 #   v2.6 — monthly_maintenance.sh: uptime-gated orchestrator for heavy monthly tasks (ZFS scrub,
-#           SMART long test). Schedule 0 3 * * * — script self-gates to monthly cadence.
+#           SMART long test). Schedule 0 0 15 * * — 15th of each month at midnight.
 #           storage_watchdog.sh + network_watchdog.sh: pool growth + connectivity watchdogs,
 #           called via SYSTEM_WATCHDOG_SCRIPTS by system_watchdog.sh (watchdog chain, no cron).
 #           webgui_watchdog.sh moved from standalone cron to SYSTEM_WATCHDOG_SCRIPTS chain.
@@ -346,17 +346,16 @@
 
 
 # ── MONTHLY MAINTENANCE ───────────────────────────────────────────────────────────────────────
-# Schedule:   0 3 * * *  (daily 3am check — script self-gates to monthly cadence)
+# Schedule:   0 0 15 * *  (15th of each month at midnight)
 # Background: YES
 #
 # Runs heavy tasks that require a long-stable, settled system. Fires only when BOTH gates pass:
 #   1. Server uptime >= MONTHLY_UPTIME_THRESHOLD_DAYS (default: 30 days)
 #   2. Last run was >= MONTHLY_RUN_INTERVAL_DAYS ago (default: 30 days)
 #
-# Why uptime-gated not cron: a scheduled reboot resets uptime. Monthly tasks (ZFS scrub,
-# SMART extended tests) need a system that has been healthy for a full month — not one that
-# just rebooted. The daily 3am cron is just the trigger. The gates inside enforce the cadence.
-# Silent exit 0 when either gate is not met — calling daily is always safe.
+# If either gate is not met on the 15th, the run is skipped until next month's 15th.
+# A reboot between the 14th and 15th will defer maintenance — which is intentional;
+# heavy tasks (ZFS scrub, SMART long test) should not run on a freshly rebooted system.
 #
 # Configure via master.conf MONTHLY_MAINTENANCE_SCRIPTS. Scripts planned but not yet built:
 #   zfs_pool_scrub.sh       ZFS pool integrity scrub (Tools/)
@@ -1436,7 +1435,7 @@
 # 0 1 * * *      1am daily:
 #   Orchestrators/daily_sync_maintenance.sh
 #
-# 0 3 * * *      3am daily (fires monthly — self-gated by uptime + interval):
+# 0 0 15 * *     15th of each month at midnight:
 #   Orchestrators/monthly_maintenance.sh
 #
 # 0 7 * * 0      Sunday 7am: