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/api/settings.go

@@ -25,6 +25,9 @@ type UpdateSettingsInput struct {
 	URLHost            *string                             `json:"url_host,omitempty" jsonschema:"keep, www or bare"`
 	URLSlash           *string                             `json:"url_slash,omitempty" jsonschema:"keep, add or remove a trailing slash"`
 	URLLowercase       *bool                               `json:"url_lowercase,omitempty" jsonschema:"lowercase the ASCII letters of addresses"`
+	LinksNewTab        *bool                               `json:"links_new_tab,omitempty" jsonschema:"open links to other sites in a new tab (rel=noopener, announced to screen readers); default true"`
+	NofollowDomains    *string                             `json:"nofollow_domains,omitempty" jsonschema:"domains whose links always get nofollow, one per line, e.g. example.com (subdomains included; no https:// and no path)"`
+	SponsoredDomains   *string                             `json:"sponsored_domains,omitempty" jsonschema:"domains whose links always get sponsored, one per line (subdomains included)"`
 	VerifyGoogle       *string                             `json:"verify_google,omitempty" jsonschema:"the Google Search Console verification code"`
 	VerifyBing         *string                             `json:"verify_bing,omitempty" jsonschema:"the Bing verification code"`
 	VerifyYandex       *string                             `json:"verify_yandex,omitempty" jsonschema:"the Yandex verification code"`

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.