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/resolver.go

@@ -57,11 +57,14 @@ type Result struct {
 	Status int    `json:"status"`
 	// Location is the absolute address a redirect answer sends the visitor
 	// to; absent on every other action.
-	Location string            `json:"location,omitempty"`
-	URL      string            `json:"url"`
-	Locale   string            `json:"locale"`
-	Staging  bool              `json:"staging"`
-	SEO      *SEO              `json:"seo"`
+	Location string `json:"location,omitempty"`
+	URL      string `json:"url"`
+	Locale   string `json:"locale"`
+	Staging  bool   `json:"staging"`
+	SEO      *SEO   `json:"seo"`
+	// Outbound is how the layer renders links to other sites (P33-16),
+	// present on ok answers.
+	Outbound *Outbound         `json:"outbound,omitempty"`
 	Sources  map[string]string `json:"-"`
 	// TypeKey and RecordID name the record behind the URL, "" when none.
 	TypeKey  string `json:"-"`
@@ -80,6 +83,35 @@ type SEO struct {
 	Verification []MetaTag  `json:"verification"`
 }
 
+// Outbound holds the settings' Links rules for links to other sites
+// (D-83): open them in a new tab, and the domains (subdomains included)
+// whose links always get nofollow or sponsored.
+type Outbound struct {
+	NewTab           bool     `json:"new_tab"`
+	NofollowDomains  []string `json:"nofollow_domains"`
+	SponsoredDomains []string `json:"sponsored_domains"`
+}
+
+// OutboundOf is the Links rules of the settings.
+func OutboundOf(s models.Settings) *Outbound {
+	return &Outbound{
+		NewTab:           s.LinksNewTab,
+		NofollowDomains:  validDomains(s.NofollowDomains),
+		SponsoredDomains: validDomains(s.SponsoredDomains),
+	}
+}
+
+// validDomains lists the valid domains of a stored list.
+func validDomains(list string) []string {
+	out := []string{}
+	for _, d := range models.DomainLines(list) {
+		if models.ValidDomain(d) {
+			out = append(out, d)
+		}
+	}
+	return out
+}
+
 // OpenGraph holds the og: values.
 type OpenGraph struct {
 	Title       string `json:"title"`
@@ -646,6 +678,7 @@ func (r *Resolver) resolveAt(ctx context.Context, db *gorm.DB, settings models.S
 	}
 
 	res.Action, res.Status, res.Locale, res.SEO = ActionOK, 200, locale, seo
+	res.Outbound = OutboundOf(settings)
 	return res, nil
 }
 

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 {