feat(HAI-002): build header and toast components

packages/dashboard/app/components/ToastContainer.tsx

@@ -0,0 +1,18 @@
+import type { Toast } from "../hooks/useToast";
+
+interface ToastContainerProps {
+  toasts: Toast[];
+  onRemove: (id: number) => void;
+}
+
+export function ToastContainer({ toasts }: ToastContainerProps) {
+  return (
+    <div className="toast-container" id="toasts">
+      {toasts.map((toast) => (
+        <div key={toast.id} className={`toast toast-${toast.type}`}>
+          {toast.message}
+        </div>
+      ))}
+    </div>
+  );
+}