fix: treat empty IMGW warning products as no warnings

lib/imgw-empty-response.ts

@@ -0,0 +1,17 @@
+export function isImgwNoProductsResponse(value: unknown) {
+  if (!value || typeof value !== "object") return false;
+  const response = value as { status?: unknown; message?: unknown };
+  return response.status === false
+    && typeof response.message === "string"
+    && response.message.toLocaleLowerCase("en-US").includes("no products were found");
+}
+
+export async function readImgwResponseBody(response: Response) {
+  const text = await response.text().catch(() => "");
+  if (!text) return { text, json: null as unknown };
+  try {
+    return { text, json: JSON.parse(text) as unknown };
+  } catch {
+    return { text, json: null as unknown };
+  }
+}