chore: import upstream snapshot with attribution

tests/unit/error-boundary-stack.test.ts

@@ -0,0 +1,12 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import { readFile } from "node:fs/promises";
+import { join } from "node:path";
+
+const repoRoot = join(import.meta.dirname, "../..");
+
+test("app error boundary does not render stack traces", async () => {
+  const source = await readFile(join(repoRoot, "src/app/error.tsx"), "utf8");
+
+  assert.doesNotMatch(source, /error\.stack/);
+});