feat(ota): add header update notification badge & 24h background check (v1.3.1)

public/index.php

@@ -478,6 +478,13 @@ $currentUser = Auth::getUsername();
 
                 <!-- Boutons d'action globaux -->
                 <div class="flex items-center gap-2.5">
+                    <!-- Badge Notification Mise à Jour Disponible -->
+                    <button id="header-update-badge" type="button" onclick="openUpdatePanel()" style="display:none;"
+                        class="inline-flex items-center gap-1.5 px-3 py-1.5 rounded-xl text-xs font-bold bg-amber-500/20 hover:bg-amber-500/30 text-amber-300 border border-amber-500/40 shadow-sm transition animate-pulse" title="Une mise à jour NexusPBX est disponible ! Cliquez pour voir les détails.">
+                        <span>🚀</span>
+                        <span id="header-update-text">Mise à jour dispo</span>
+                    </button>
+
                     <button id="btn-test-ami" type="button"
                         class="inline-flex items-center gap-2 px-3.5 py-2 rounded-xl text-xs font-semibold bg-anthracite-750 hover:bg-anthracite-700 text-slate-100 border border-anthracite-600 transition">
                         <span id="ami-dot" class="w-2 h-2 rounded-full bg-emerald-400"></span>