10dfc8609d
Commit e20ef94 set the default to https://flights.test.aeroflot.ru/api,
which broke the browser client (no CORS headers on the test env;
scripts/dev-server.mjs is the only layer that can bypass it).
Keep PROD_ORIGIN pointing at the test env for SEO, but restore
API_BASE_URL default to http://localhost:8080/api with a comment
explaining the proxy chain: dev → Express+curl → flights.test.aeroflot.ru.
Production deployments continue to set API_BASE_URL explicitly.