Opens a local->remote forward on demand so a gateway-side dev server URL
resolves to the gateway, not the laptop rendering the webview.
One lease per remote port, reused across pages and expired after 15
minutes; the port allowlist is deliberately absent, since the transport
we are already authenticated on is the security boundary and a curated
list just means the next framework default silently fails.
Lease and capability shape adapted from #87243.
Co-authored-by: tuancookiez-hub <tuancookiez-hub@users.noreply.github.com>
Brooklyn Nicholson