The websockets dials got proxy=None but the three HTTP /json/version dials
(CDP override discovery, is_browser_debug_ready used by Lightpanda and the
real-profile readiness check, and surviving-Chrome detection) still resolved
via getproxies(), so under a system/env proxy discovery fell back to the raw
http:// URL, readiness never fired and /browser connect reported not ready.
loopback_request_kwargs() sits next to loopback_connect_kwargs() and is used
at all three sites (ProxyHandler({}) opener for the urllib one).
add_loopback_no_proxy turned an operator NO_PROXY=* into '*,127.0.0.1,...',
which urllib/requests no longer treat as the wildcard, flipping bypass-all
configs into proxy-all. A wildcard in either casing now leaves env untouched.
is_loopback_host also accepts any loopback IP literal (127.x, ::ffff:127.0.0.1).
Review finding: HTTP /json/version dials still proxied loopback; NO_PROXY=* wildcard broken by append.
