diff --git a/.gitea/workflows/ci.yml b/.gitea/workflows/ci.yml
index 26328ee..728b1d1 100644
--- a/.gitea/workflows/ci.yml
+++ b/.gitea/workflows/ci.yml
@@ -91,6 +91,9 @@ jobs:
           npm install -g playwright
           npx playwright install --with-deps chromium
       - name: Start preview server
+        # CAR-1218: bind to 127.0.0.1 (IPv4) not localhost. The act runner
+        # resolves 'localhost' to ::1 (IPv6) and the preview server does not
+        # get a reachable IPv4 socket, so wait-on times out.
         run: |
           npx vite preview --host 127.0.0.1 --port 4173 &
           npx wait-on http://127.0.0.1:4173/ --timeout 30000