Move remainder container updates from weekly to monthly

Daily updates daily containers, weekly updates its sync-window containers,
monthly now handles everything else via MONTHLY_MAINTENANCE_SCRIPTS.

Plugin/unraid/user_script_plug-in.sh

@@ -71,7 +71,7 @@
 #           Correct schedules verified against script headers. sunday_morning_coffee_report
 #           and rsync_emby_fallback added as separate scheduled entries.
 #   v2.3 — intermediate_sync_maintenance.sh new 4-hour orchestrator (arr_sync + artwork).
-#           docker_update.sh (normal + --remainder): daily/weekly image pulls.
+#           docker_update.sh (normal + --remainder): daily/monthly image pulls.
 #           downloaders_reset.sh: slskd + SABnzbd + qBittorrent maintenance.
 #           arr_sync.sh: bidirectional Lidarr/Sonarr/Radarr library mesh.
 #           lidarr_missing_art.sh: fetch missing album/artist artwork.
@@ -330,8 +330,7 @@
 #   7. Start remote containers  dependency order, new image, verify each container up
 #   8. Start local containers   dependency order, new image, verify each container up
 #   9. docker_weekly_restart.sh restart less-critical services: NextCloud, AdGuard, Immich
-# 10. docker_update.sh --remainder  pull latest images for all containers not in daily/weekly lists
-#  11. WEEKLY_MAINTENANCE_SCRIPTS — clear_logs.sh + playback_aware_*.sh discovery scripts.
+#  10. WEEKLY_MAINTENANCE_SCRIPTS — clear_logs.sh + playback_aware_*.sh discovery scripts.
 #                                playback_aware_lidarr_discovery.sh: 0–5 music adds/week
 #                                  based on your Emby play history + Last.fm similar artists.
 #                                playback_aware_radarr_discovery.sh: 0–5 movie adds/week
@@ -660,10 +659,10 @@
 #     Containers stay running during the pull. Rebuilds containers that received a new image.
 #     docker_daily_restart.sh restarts the rest. Toggle: DAILY_CONTAINER_UPDATES in master.conf.
 #
-#   Remainder (weekly) — targets all running containers not in managed lists.
-#     Excludes daily list, weekly restart list, emby+critical-data sync-window containers,
+#   Remainder (monthly) — targets all running containers not in managed lists.
+#     Excludes daily list, emby+critical-data sync-window containers,
 #     and fallback containers owned by the remote server's update cycle.
-#     Rebuilds containers that received a new image. Toggle: WEEKLY_REMAINING_UPDATES in master.conf.
+#     Rebuilds containers that received a new image. Toggle: MONTHLY_REMAINING_UPDATES in master.conf.
 #
 # bash /boot/config/plugins/varaverk/Docker_Essentials/docker_update.sh --dry-run
 # bash /boot/config/plugins/varaverk/Docker_Essentials/docker_update.sh --status