fix(cli): improve browser control errors

src/browser/client.test.ts

@@ -0,0 +1,24 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import { browserStatus } from "./client.js";
+
+describe("browser client", () => {
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  it("wraps connection failures with a gateway hint", async () => {
+    const refused = Object.assign(new Error("connect ECONNREFUSED 127.0.0.1"), {
+      code: "ECONNREFUSED",
+    });
+    const fetchFailed = Object.assign(new TypeError("fetch failed"), {
+      cause: refused,
+    });
+
+    vi.stubGlobal("fetch", vi.fn().mockRejectedValue(fetchFailed));
+
+    await expect(browserStatus("http://127.0.0.1:18791")).rejects.toThrow(
+      /Start .*gateway/i,
+    );
+  });
+});