feat: links settings and outbound rules in resolve

- migration 202610280003: settings links_new_tab (default on),
  nofollow_domains and sponsored_domains; robots llms_enabled and
  llms_intro (used by the llms.txt commit)
- SEO settings Links tab: the new-tab switch and the two domain lists,
  one domain per line, lowercased, refused with settings.domain_invalid
  naming the line; writable through seo_update_settings
- the resolve answer of an ok page carries outbound {new_tab,
  nofollow_domains, sponsored_domains}; no existing key changes

controllers/settings.go

@@ -63,7 +63,12 @@ func (c settingsAdminController) FormBeforeUpdate(ctx context.Context, model any
 	if !ok || s == nil {
 		return nil
 	}
-	return problemsError(ctx, translator(c.app), s.Problems())
+	if err := problemsError(ctx, translator(c.app), s.Problems()); err != nil {
+		return err
+	}
+	s.NofollowDomains = models.NormalizeDomains(s.NofollowDomains)
+	s.SponsoredDomains = models.NormalizeDomains(s.SponsoredDomains)
+	return nil
 }
 
 // FormBeforeCreate checks a created row like an update.