Storage-mode awareness pass + doc update for System_Essentials through Partnership

All state/data file paths in scripts and PHP now resolve via STATE_DIR / DATA_DIR /
PERSISTENT_CONF_CACHE instead of hardcoded /boot/config/ or /tmp/ paths, so the
ecosystem works in both internal and appdata storage modes.

PHP layer (watchdog.php, partnership.php, fallback.php, monitor.php, snapshot.php,
config.php): all state reads switched to STATE_DIR constant; remote state reads use
the new vv_remote_state_cmd() helper which resolves the remote's SCRIPTS_DIR via
their varaverk.cfg before building the path.

conf_sync.sh: fixed SCRIPTS_ROOT → SCRIPTS_DIR bug on MY_CONF path; added
_remote_scripts_dir() to resolve partner's SCRIPTS_DIR before SCP pull.

fallback.php page: added controls card (PARTNERSHIP_ENABLED, FALLBACK_ENABLED,
FALLBACK_RSYNC_ENABLED toggles), status grid, and settings card.

README and Manual updated for System_Essentials, Watchdogs, Fallback, Rsync,
Media, Monitors, Orchestrators, Partnership: added new scripts (conf_sync,
conf_cache_save/restore, conf_cache_watchdog, play_state_sync, start_webhook_listener,
upgrade_webhook_handler), corrected all stale /boot/config/ state file paths to
$STATE_DIR/$DATA_DIR, noted webgui/php_fpm/mover/user_scripts scripts moved to
Plugin/unraid/System_Essentials, fixed start_webhook_listener.sh header (Node.js,
not PHP -S).

Plugin/unraid/include/partnership.php

@@ -10,7 +10,7 @@ require_once __DIR__ . '/common.php'; // vv_system_info(), vv_docker_containers(
 function vv_pt_config(): array {
     $v = vv_conf_vars();
     $offlineDays = null;
-    $odFile = '/boot/config/partnership_offline_days.db';
+    $odFile = STATE_DIR . '/partnership_offline_days.db';
     if (file_exists($odFile)) {
         $raw = trim(@file_get_contents($odFile) ?: '');
         if (is_numeric($raw)) $offlineDays = (int)$raw;
@@ -209,12 +209,11 @@ function vv_pt_nodes(): array {
 
         // Fallback state
         $fbState = 'UNKNOWN';
-        $fbPath  = '/boot/config/fallback_state.db';
         if ($isMe) {
-            $fb = vv_pt_read_db($fbPath);
+            $fb = vv_pt_read_db(STATE_DIR . '/fallback_state.db');
             $fbState = $fb['state'] ?? 'UNKNOWN';
         } elseif ($ts['online'] && $ts['ip'] && $mySshKey) {
-            $out = vv_pt_ssh($ts['ip'], $mySshKey, 'cat /boot/config/fallback_state.db 2>/dev/null');
+            $out = vv_pt_ssh($ts['ip'], $mySshKey, vv_remote_state_cmd('fallback_state.db'));
             if ($out) {
                 $fb = [];
                 foreach (explode("\n", $out) as $line) {
@@ -226,7 +225,7 @@ function vv_pt_nodes(): array {
         }
 
         // Partnership DB — local only (each server writes its own)
-        $dbPath = "/boot/config/partnership_{$hostname}.db";
+        $dbPath = STATE_DIR . "/partnership_{$hostname}.db";
         $ptDb   = vv_pt_read_db($dbPath);
 
         // System info