Watchdogs/ folder + host conf rename

Move all watchdog scripts to a dedicated Watchdogs/ folder:
  Docker_Essentials/docker_watchdog.sh   → Watchdogs/
  unRAID_Essentials/system_watchdog.sh   → Watchdogs/
  unRAID_Essentials/resource_watchdog.sh → Watchdogs/
  Orchestrators/watchdog_orchestrator.sh → Watchdogs/
  Tools/watchdog_skip_list_manager.sh    → Watchdogs/

Rename host config files:
  master_host1.conf → host1.conf
  master_host2.conf → host2.conf

Update all references across the ecosystem:
  master.conf: WATCHDOG_ORCHESTRATOR_SCRIPTS paths → Watchdogs/
  load_config.sh: host*.conf glob + all comments
  git_pull_execute.sh: sparse checkout glob + all comments
  Partnership/ssh_setup.sh: HOST_CONF path construction
  user_script_plug-in.sh: all script paths + per-host conf path
  common.sh, README.md, README-User_Script_Plug-in.md: comment refs
  All Partnership, Fallback, Monitors, Transcodes, Tools scripts: comment refs

Docker_Essentials/docker_weekly_restart.sh

@@ -43,7 +43,7 @@
 # CONFIGURATION
 # ==============================================================================================
 #
-# master_host*.conf
+# host*.conf
 #
 #   HOST*_WEEKLY_RESTART_CONTAINERS
 #       Containers restarted weekly. Aliased by detect_hosts() →
@@ -108,7 +108,7 @@ detect_hosts
 
 if [[ ${#WEEKLY_RESTART_CONTAINERS[@]} -eq 0 ]]; then
     warn "WEEKLY_RESTART_CONTAINERS is empty for $MY_ID — nothing to restart"
-    warn "Check HOST*_WEEKLY_RESTART_CONTAINERS in master_host*.conf"
+    warn "Check HOST*_WEEKLY_RESTART_CONTAINERS in host*.conf"
     exit 0
 fi