Replace the boolean browser-managed target validator with
resolveBrowserManagedTarget, which returns the parsed canonical absolute URL,
and hand that exact value to the host. Previously the raw href was passed on,
so a relative target was re-resolved against document.baseURI and a hostile
<base> could send the navigation to an origin the policy never approved.
STO-08 stays UNVERIFIED: the capability spec does not exercise the system
picker, so the receiver-binding hypothesis is neither reproduced nor refuted
and no source change was made for it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
