Make PARTNERSHIP_ENABLED the authoritative gate for all cross-server operations

Adds require_partnership() to common.sh — exits cleanly when PARTNERSHIP_ENABLED=false.
Removes FALLBACK_PARTNERSHIP_REQUIRED toggle — partnership is now always required,
not optional. Cross-server scripts (rsync, conf sync, fallback, arr sync, play state,
backup verify) all call require_partnership after detect_hosts.

Plugin/unraid/include/monitor.php

@@ -56,14 +56,13 @@ function vv_fallback_state(): array {
     $enabled   = ($vars['FALLBACK_ENABLED']           ?? 'false') === 'true';
     $interval  = (int)($vars['FALLBACK_CHECK_INTERVAL']    ?? 30);
     $reqStrikes = (int)($vars['FALLBACK_HANDBACK_STRIKES'] ?? 3);
-    $ptRequired = ($vars['FALLBACK_PARTNERSHIP_REQUIRED']  ?? 'true') === 'true';
     $suspendAfter = (int)($vars['FALLBACK_PARTNERSHIP_SUSPEND_AFTER'] ?? 120);
 
     $stateFile = '/tmp/fallback_state.db';
     if (!file_exists($stateFile)) {
         return ['state' => 'UNKNOWN', 'enabled' => $enabled, 'check_interval' => $interval,
                 'handback_strikes' => 0, 'handback_strikes_required' => $reqStrikes,
-                'partnership_required' => $ptRequired, 'partnership_suspended' => false,
+                'partnership_suspended' => false,
                 'partner_lost_at' => 0, 'partnership_suspend_after' => $suspendAfter];
     }
     $raw = [];
@@ -83,7 +82,6 @@ function vv_fallback_state(): array {
         'enabled'                    => $enabled,
         'check_interval'             => $interval,
         'handback_strikes_required'  => $reqStrikes,
-        'partnership_required'       => $ptRequired,
         'partnership_suspend_after'  => $suspendAfter,
     ];
 }