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/theme-provider.tsx

@@ -0,0 +1,7 @@
+"use client"
+import { ThemeProvider as NextThemesProvider } from "next-themes"
+import type { ThemeProviderProps } from "next-themes"
+
+export function ThemeProvider({ children, ...props }: ThemeProviderProps) {
+  return <NextThemesProvider {...props}>{children}</NextThemesProvider>
+}