URL validation centralises link-local (fe80::/10) into BLOCKED_IPV6_PREFIXES
alongside ULA (fc00::/7), so direct `http://[fe80::N]/` URLs are rejected
the same way `http://[fc00::]/` already was. Previously the link-local
guard only fired during DNS AAAA resolution, leaving direct-literal URLs
to slip through.
Prefix range covers fe80::-febf::: ['fe8','fe9','fea','feb'].
Regression test: validateNavigationUrl('http://[fe80::2]/') now throws
with /cloud metadata/i.
Contributed by @hiSandog (#1249).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>