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

classes/settings_write.go

@@ -37,7 +37,8 @@ var SettingsColumns = []string{
 	"site_name", "twitter_site", "title_template", "home_template",
 	"default_description", "default_og_image", "query_params",
 	"noindex_paths", "search_paths", "url_host", "url_slash",
-	"url_lowercase", "verify_google", "verify_bing", "verify_yandex",
+	"url_lowercase", "links_new_tab", "nofollow_domains",
+	"sponsored_domains", "verify_google", "verify_bing", "verify_yandex",
 	"verify_other", "verify_files", "csv_delimiter",
 }
 
@@ -57,6 +58,9 @@ func SettingsValues(st models.Settings) map[string]any {
 		"url_host":            st.URLHost,
 		"url_slash":           st.URLSlash,
 		"url_lowercase":       st.URLLowercase,
+		"links_new_tab":       st.LinksNewTab,
+		"nofollow_domains":    st.NofollowDomains,
+		"sponsored_domains":   st.SponsoredDomains,
 		"verify_google":       st.VerifyGoogle,
 		"verify_bing":         st.VerifyBing,
 		"verify_yandex":       st.VerifyYandex,
@@ -119,12 +123,22 @@ func SetSettingsValue(st *models.Settings, column string, v any) error {
 		st.VerifyYandex, err = text()
 	case "csv_delimiter":
 		st.CSVDelimiter, err = text()
+	case "nofollow_domains":
+		st.NofollowDomains, err = text()
+	case "sponsored_domains":
+		st.SponsoredDomains, err = text()
 	case "url_lowercase":
 		b, ok := v.(bool)
 		if !ok {
 			return fmt.Errorf("golem15.seo: settings %s is not a bool", column)
 		}
 		st.URLLowercase = b
+	case "links_new_tab":
+		b, ok := v.(bool)
+		if !ok {
+			return fmt.Errorf("golem15.seo: settings %s is not a bool", column)
+		}
+		st.LinksNewTab = b
 	case "query_params":
 		var out []models.QueryParam
 		if err = list(&out); err == nil {
@@ -256,6 +270,8 @@ func (s *Service) SaveSettings(ctx context.Context, tx *gorm.DB, in SettingsWrit
 	if len(problems) > 0 {
 		return models.Settings{}, &ProblemsError{Problems: problems}
 	}
+	row.NofollowDomains = models.NormalizeDomains(row.NofollowDomains)
+	row.SponsoredDomains = models.NormalizeDomains(row.SponsoredDomains)
 	now := time.Now().UTC()
 	row.UpdatedAt = &now
 	if err := tx.Save(&row).Error; err != nil {