feat: initial commit — asaas-checkout template white-label

Template genérico de checkout com ASAAS, parametrizado via env vars.
Inclui fluxo completo: checkout → pedido → polling → webhook → admin.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

components/auth-guard.tsx

@@ -0,0 +1,25 @@
+"use client"
+
+import { useEffect } from "react"
+import { useRouter } from "next/navigation"
+import { useToast } from "@/components/ui/use-toast"
+import type React from "react" // Added import for React
+
+export function AuthGuard({ children }: { children: React.ReactNode }) {
+  const router = useRouter()
+  const { toast } = useToast()
+
+  useEffect(() => {
+    const isLoggedIn = localStorage.getItem("isLoggedIn")
+    if (!isLoggedIn) {
+      toast({
+        title: "Acesso negado",
+        description: "Faça login para acessar a área administrativa.",
+        variant: "destructive",
+      })
+      router.push("/login")
+    }
+  }, [router, toast])
+
+  return <>{children}</>
+}