- Extract shared parseHostEntries() to deduplicate setAllowedHosts/setAdditionalBlockedHosts
- Add isHostnameAllowed() and propagate hostname allow-list check in resolver
- Move OAuth2 custom mapper URL SSRF validation to save-time (Oauth2ClientDataValidator)
- Remove runtime SSRF checks from CustomOAuth2ClientMapper and GithubOAuth2ClientMapper
(custom URL now validated at save; GitHub emailUrl is server config, not user input)
- Replace example.com with 8.8.8.8 in resolver test to avoid DNS dependency