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/site-header.tsx

@@ -0,0 +1,69 @@
+"use client"
+
+import { useState } from "react"
+import Link from "next/link"
+import { useRouter } from "next/navigation"
+import { Button } from "@/components/ui/button"
+import { Sheet, SheetContent, SheetTitle, SheetTrigger } from "@/components/ui/sheet"
+import { useAuth } from "@/lib/auth-context"
+import { User, Menu, X, ShoppingBag } from "lucide-react"
+import { appConfig } from "@/lib/config"
+
+export function SiteHeader() {
+  const { isLoggedIn } = useAuth()
+  const router = useRouter()
+  const [isMenuOpen, setIsMenuOpen] = useState(false)
+
+  return (
+    <header className="sticky top-0 z-50 w-full bg-white border-b">
+      <div className="container flex h-16 items-center justify-between">
+        <Link href="/" className="flex items-center space-x-2">
+          {appConfig.logoUrl ? (
+            <img src={appConfig.logoUrl} alt={appConfig.name} className="h-8 w-auto" />
+          ) : (
+            <span className="text-xl font-bold text-primary">{appConfig.name}</span>
+          )}
+        </Link>
+
+        <nav className="hidden md:flex items-center space-x-6">
+          <Button asChild>
+            <Link href="/comprar">
+              <ShoppingBag className="mr-2 h-4 w-4" />
+              Ver produtos
+            </Link>
+          </Button>
+        </nav>
+
+        <Sheet open={isMenuOpen} onOpenChange={setIsMenuOpen}>
+          <SheetTrigger asChild>
+            <Button variant="ghost" size="icon" className="md:hidden">
+              {isMenuOpen ? <X className="h-5 w-5" /> : <Menu className="h-5 w-5" />}
+            </Button>
+          </SheetTrigger>
+          <SheetContent side="right" className="w-[300px]">
+            <SheetTitle className="sr-only">Menu</SheetTitle>
+            <nav className="flex flex-col space-y-4 mt-4">
+              <Button
+                className="w-full"
+                onClick={() => { setIsMenuOpen(false); router.push("/comprar") }}
+              >
+                <ShoppingBag className="mr-2 h-4 w-4" />
+                Ver produtos
+              </Button>
+              {isLoggedIn && (
+                <Button
+                  variant="outline"
+                  onClick={() => { setIsMenuOpen(false); router.push("/admin") }}
+                  className="w-full"
+                >
+                  <User className="h-4 w-4 mr-2" />
+                  Dashboard
+                </Button>
+              )}
+            </nav>
+          </SheetContent>
+        </Sheet>
+      </div>
+    </header>
+  )
+}