Structural reorganization: watchdog taxonomy + server_reboot integration

Watchdog renames and moves:
  system_watchdog.sh → stability_watchdog.sh (last line of defense — reboots)
  storage_watchdog.sh → Watchdogs/System/storage_watchdog.sh
  webgui_restart.sh → Watchdogs/System/webgui_watchdog.sh (renamed to match folder convention)

New thin orchestrator:
  Watchdogs/system_watchdog.sh — runs SYSTEM_WATCHDOG_SCRIPTS from master.conf
  Sits between docker_watchdog and stability_watchdog in the orchestrator tier chain
  System/ subfolder is the growth seam for future system component watchdogs

master.conf:
  WATCHDOG_ORCHESTRATOR_SCRIPTS updated — storage removed, system_watchdog added as tier
  SYSTEM_WATCHDOG_SCRIPTS array added — storage + webgui

server_reboot.sh:
  Calls array_stopping.sh before VM shutdown for guaranteed safe array stop
  Removed raw rc.docker stop and exit trap — orchestrator owns container shutdown

unRAID_Essentials/Manual-Unraid_Essentials.md

@@ -13,7 +13,7 @@ adding or reordering scripts at array start.
 ## ━━━ CONTENTS ━━━
 
 - [ARRAY_START_SCRIPTS Order](#array_start_scripts-order)
-- [webgui_restart.sh](#webgui_restartsh)
+- [webgui_watchdog.sh](#webgui_watchdogsh)
 - [inotify_tuning.sh](#inotify_tuningsh)
 - [php_fpm_max_children.sh](#php_fpm_max_childrensh)
 - [docker_syslog_filter.sh](#docker_syslog_filtersh)
@@ -32,7 +32,7 @@ adding or reordering scripts at array start.
 All scripts use a two-tier output model: `echo` lines are always visible; `log`
 lines only appear when `--log` is passed.
 
-**Daemon scripts** (`webgui_restart.sh`): run on every cycle. Without `--log`, only
+**Daemon scripts** (`webgui_watchdog.sh`): run on every cycle. Without `--log`, only
 state transitions, warnings, errors, and the clean-cycle conclusion line are visible.
 Per-check detail suppressed.
 
@@ -76,7 +76,7 @@ generates veth messages — these will appear in syslog if the filter isn't acti
 
 ---
 
-## webgui_restart.sh
+## webgui_watchdog.sh
 
 ### Escalation Logic
 
@@ -113,7 +113,7 @@ WEBGUI_EMHTTP_WAIT=30           # seconds after emhttp restart before recheck
 
 ```bash
 # Check which services are running:
-webgui_restart.sh --status
+webgui_watchdog.sh --status
 
 # Try manual restart sequence (same as the script):
 /etc/rc.d/rc.nginx restart
@@ -196,8 +196,8 @@ grep "^pm.max_children" /etc/php83/php-fpm.d/www.conf
 
 ```bash
 # Check PHP-FPM worker utilization (requires system_tuning_monitor.sh in Monitors/):
-# Look at the webgui_restart.sh escalation — step 2 (php-fpm restart) is specifically
-# for worker exhaustion. If webgui_restart.sh is regularly hitting step 2, the
+# Look at the webgui_watchdog.sh escalation — step 2 (php-fpm restart) is specifically
+# for worker exhaustion. If webgui_watchdog.sh is regularly hitting step 2, the
 # pm.max_children value may still be too low, or there's a PHP worker leak.
 
 # Check running worker count: