fix: add authentication to file downloads

dashboard/frontend/src/lib/api.js

@@ -197,3 +197,25 @@ export function getInfoEngineItem(id) {
 export function put(path, data) {
   return request(path, { method: "PUT", json: data });
 }
+
+export async function download(path, filename) {
+  const headers = {};
+  if (token) headers["Authorization"] = `Bearer ${token}`;
+
+  const r = await fetch(`${BASE}/files/download?path=${encodeURIComponent(path)}`, {
+    method: "GET",
+    headers,
+  });
+
+  if (!r.ok) throw new Error(`HTTP ${r.status}`);
+
+  const blob = await r.blob();
+  const url = window.URL.createObjectURL(blob);
+  const a = document.createElement("a");
+  a.href = url;
+  a.download = filename;
+  document.body.appendChild(a);
+  a.click();
+  window.URL.revokeObjectURL(url);
+  document.body.removeChild(a);
+}