new Response(blob) reads the body through blob.stream(), which jsdom's Blob
does not implement on Node 22 — the version the Dockerfile builds with. The
test passed locally on Node 24 and threw "object.stream is not a function" in
CI. Nothing in it asserts on the body, only that the object URL and filename
reach the anchor, so a string body is equivalent and works on both.
Surfaced by the CI workflow added in this branch, which is the first thing in
this repo to run the frontend suite anywhere but a developer's machine.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
