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/dashboard-header.tsx

@@ -0,0 +1,23 @@
+import type React from "react" // Added import for React
+
+interface DashboardHeaderProps {
+  heading: string
+  text?: string
+  children?: React.ReactNode
+}
+
+export function DashboardHeader({ heading, text, children }: DashboardHeaderProps) {
+  return (
+    <div className="flex items-center justify-between px-2">
+      <div className="grid gap-1">
+        <h1 className="font-heading text-3xl font-bold tracking-tight">{heading}</h1>
+        {text && <p className="font-sans text-lg text-muted-foreground">{text}</p>}
+        <p className="text-sm text-muted-foreground mt-2 font-sans">
+          Gerencie seus certificados digitais, acompanhe vendas e monitore o desempenho em tempo real. Todas as
+          ferramentas que você precisa em um só lugar.
+        </p>
+      </div>
+      <div className="flex items-center gap-2">{children}</div>
+    </div>
+  )
+}