chore: import upstream snapshot with attribution

tests/unit/browser-pool-optional-import.test.ts

@@ -0,0 +1,27 @@
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import path from "node:path";
+import { describe, it } from "node:test";
+import { fileURLToPath } from "node:url";
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const REPO_ROOT = path.resolve(__dirname, "../..");
+const BROWSER_POOL_PATH = path.join(REPO_ROOT, "open-sse/services/browserPool.ts");
+
+describe("browserPool optional cloakbrowser import", () => {
+  it("keeps cloakbrowser out of static dynamic import resolution", () => {
+    const source = readFileSync(BROWSER_POOL_PATH, "utf8");
+
+    assert.equal(
+      /import\(\s*["']cloakbrowser["']\s*\)/.test(source),
+      false,
+      "cloakbrowser must remain runtime-optional; static dynamic import triggers Turbopack resolution"
+    );
+    assert.match(
+      source,
+      /Turbopack resolve it during route compilation/,
+      "the computed import rationale should stay documented near the helper"
+    );
+    assert.match(source, /return \["cloak", "browser"\]\.join\(""\);/);
+  });
+});