Add is_forbidden_ip() (loopback, RFC1918, link-local incl. 169.254.169.254,
broadcast, documentation, 0.0.0.0/::, IPv6 unique-local fc00::/7, IPv4-mapped
IPv6) and SsrfGuardResolver (impl reqwest::dns::Resolve) that resolves and
rejects forbidden addresses at connect time, closing the DNS-rebinding bypass.
Wired into the navigation client and the JS fetch()/XHR path. The
--allow-private-network / OBSCURA_ALLOW_PRIVATE_NETWORK escape hatch is kept.
Co-authored-by: charlesmamane26-sketch <[email protected]>
