fix: corrige avisos de estilo do Tailwind CSS

- bg-gradient-to-r -> bg-linear-to-r
- after:start-[4px] -> after:start-1
- z-[60] -> z-60

frontend/src/app/admin/configuracoes/page.tsx

@@ -488,7 +488,7 @@ export default function ConfiguracoesPage() {
                   onChange={(e) => setShowPartnerBadge(e.target.checked)}
                   className="sr-only peer"
                 />
-                <div className="w-14 h-7 bg-gray-200 peer-focus:outline-none peer-focus:ring-4 peer-focus:ring-primary/20 dark:peer-focus:ring-primary/30 rounded-full peer dark:bg-white/10 peer-checked:after:translate-x-full rtl:peer-checked:after:-translate-x-full peer-checked:after:border-white after:content-[''] after:absolute after:top-0.5 after:start-[4px] after:bg-white after:border-gray-300 after:border after:rounded-full after:h-6 after:w-6 after:transition-all dark:border-gray-600 peer-checked:bg-primary"></div>
+                <div className="w-14 h-7 bg-gray-200 peer-focus:outline-none peer-focus:ring-4 peer-focus:ring-primary/20 dark:peer-focus:ring-primary/30 rounded-full peer dark:bg-white/10 peer-checked:after:translate-x-full rtl:peer-checked:after:-translate-x-full peer-checked:after:border-white after:content-[''] after:absolute after:top-0.5 after:start-1 after:bg-white after:border-gray-300 after:border after:rounded-full after:h-6 after:w-6 after:transition-all dark:border-gray-600 peer-checked:bg-primary"></div>
               </label>
             </div>
 

frontend/src/components/Header.tsx

@@ -91,7 +91,7 @@ export default function Header() {
     <>
       {/* Admin Bar - aparece apenas para usuários logados */}
       {isLoggedIn && (
-        <div className="w-full bg-secondary dark:bg-black py-1.5 px-4 z-[60] relative">
+        <div className="w-full bg-secondary dark:bg-black py-1.5 px-4 z-60 relative">
           <div className="container mx-auto flex items-center justify-between">
             <div className="flex items-center gap-2 text-xs text-gray-400">
               <i className="ri-shield-user-line text-primary"></i>

frontend/src/components/admin/BackupManager.tsx

@@ -192,7 +192,7 @@ export function BackupManager() {
   return (
     <div className="space-y-6">
       {/* Botão de Criar Backup */}
-      <div className="bg-gradient-to-r from-blue-50 to-blue-100 dark:from-blue-900/20 dark:to-blue-800/20 border border-blue-200 dark:border-blue-800 rounded-2xl p-6">
+      <div className="bg-linear-to-r from-blue-50 to-blue-100 dark:from-blue-900/20 dark:to-blue-800/20 border border-blue-200 dark:border-blue-800 rounded-2xl p-6">
         <div className="flex flex-col sm:flex-row items-start sm:items-center justify-between gap-4">
           <div>
             <h3 className="text-lg font-bold text-gray-900 dark:text-white mb-2 flex items-center gap-2">