refactor(admin): migrate registration moderation to new architecture
Move registration moderation to RegistrationModerationController:
list pending (preg=0) + approve/approve-all/delete/delete-all/delete-by-ip.
Add RegistrationModerationRepositoryInterface (Eloquent User/IpHistory),
GetPendingRegistrations/Approve/Delete use cases and RegistrationRowMapper
(adds raw integer IP for the remove-by-IP action). Convert GET ?mod= mutations
to POST forms with CSRF and PRG redirects. Remove includes/reg.php and the
dispatcher entry; point both sidebars at /admin/registrations.
list pending (preg=0) + approve/approve-all/delete/delete-all/delete-by-ip.
Add RegistrationModerationRepositoryInterface (Eloquent User/IpHistory),
GetPendingRegistrations/Approve/Delete use cases and RegistrationRowMapper
(adds raw integer IP for the remove-by-IP action). Convert GET ?mod= mutations
to POST forms with CSRF and PRG redirects. Remove includes/reg.php and the
dispatcher entry; point both sidebars at /admin/registrations.