When Hermes WebUI runs behind a reverse proxy with HTTP basic auth
(e.g. Caddy basic_auth), browsers embed credentials in the page URL.
The Fetch API and EventSource reject requests constructed from URLs
that include credentials (per Fetch spec, all modern browsers).
Fix: construct all fetch() and EventSource URLs via
new URL(path, location.origin) which strips credentials from the
base URL. Add credentials:"include" to ensure auth headers are
forwarded on each request.
