ci: add a browser fetch test

.github/workflows/zig-test.yml

@@ -66,6 +66,25 @@ jobs:
             zig-out/bin/lightpanda
           retention-days: 1
 
+  browser-fetch:
+    name: browser fetch
+    needs: zig-build-dev
+
+    # Don't run the CI with draft PR.
+    if: github.event.pull_request.draft == false
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: download artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: lightpanda-build-dev
+
+      - run: chmod a+x ./lightpanda
+
+      - run: ./lightpanda fetch https://httpbin.io/xhr/get
+
   zig-test:
     name: zig test