Fix dead/incorrect vars in Plugin/ found during full codebase audit

- WEBGUI_PHP_WAIT was referenced by webgui_watchdog.sh but never defined
  in master.conf, always silently falling back to a hardcoded default
- arrs.php/confform.php still pointed at Media/ for arr cleanup/discovery
  scripts moved to Arrs_Stack/ in b4bc926 — broke the Arrs page's stats
  and the per-script settings editor for those scripts
- docker_folders.php read directly from the optional folder.view3 plugin's
  file instead of Varaverk's own docker_folders.json (the primary store
  since the Docker tab got its own config) — left the Monitor page's
  Docker Folders widget empty on any host without folder.view3 installed
- vv_wd_remote_data() read remote watchdog state files from hardcoded
  /tmp or /boot/config paths instead of the remote's actual STATE_DIR
  (which resolves dynamically and can differ under flash mode) — remote
  node's Watchdog panel was always empty; same wrong path also used for
  two local reads (system_watchdog_oom.db, watchdog_appdata_growth.db)
- rsync.php referenced a {HOST}_MONTHLY_SYNC_SHARES conf var that never
  existed (monthly_maintenance.sh has no rsync section) — nulled out to
  match the existing pattern used for the fallback window
- vv_arr_node_names() did a pointless identity array_map
- vv_dk_webui() had its own duplicate local-IP resolution instead of
  using vv_local_ip(), despite config.php's comment claiming that exact
  duplication was already consolidated

Plugin/unraid/api/rsync.php

@@ -83,7 +83,8 @@ $winArrayDefs = [
     'intermediate' => ['INTERMEDIATE_MAINTENANCE_SCRIPTS', "{$myId}_INTERMEDIATE_SYNC_SHARES"],
     'daily'        => ['DAILY_MAINTENANCE_SCRIPTS',        "{$myId}_DAILY_SYNC_SHARES"],
     'weekly'       => ['WEEKLY_MAINTENANCE_SCRIPTS',       "{$myId}_WEEKLY_SYNC_SHARES"],
-    'monthly'      => ['MONTHLY_MAINTENANCE_SCRIPTS',      "{$myId}_MONTHLY_SYNC_SHARES"],
+    // monthly_maintenance.sh has no rsync section (ZFS scrub/SMART tests only) — no shares var exists.
+    'monthly'      => ['MONTHLY_MAINTENANCE_SCRIPTS',      null],
     'fallback'     => [null,                               null],
 ];
 $winArrays = [];