feat: publisher, local business and home crumb settings

- Publisher and Local business tabs with the C20 refusals (sameAs lines,
  person as local business, address, times, country, coordinates)
- the publisher node from the settings, as an Organization, a Person or
  the chosen local business type with address, geo and opening hours
- P8 publisher preview with Google's required and recommended findings
  (classes/schema Validate)
- the home crumb name on the General tab; every new key in the settings
  API and seo_update_settings

classes/structured.go

@@ -2,6 +2,7 @@ package classes
 
 import (
 	"context"
+	"encoding/json"
 	"strconv"
 	"strings"
 
@@ -220,3 +221,50 @@ func (s *Service) structuredData(ctx context.Context, db *gorm.DB, settings mode
 	res.JSONLD = graph
 	return nil
 }
+
+// PublisherPreview is the view model of the settings' P8 partial: the
+// generated publisher node as indented JSON and its findings as lines, or
+// the all-good line.
+type PublisherPreview struct {
+	JSON     string
+	Findings []string
+	AllGood  string
+}
+
+// FindingText renders a finding with the graph copy of the request locale.
+func (s *Service) FindingText(ctx context.Context, typ string, f schema.Finding) string {
+	key := "golem15.seo::lang.graph.recommended"
+	if f.Level == schema.LevelRequired {
+		key = "golem15.seo::lang.graph.required"
+	}
+	return s.PhraseCtx(ctx, key, map[string]string{"property": f.Property, "type": typ})
+}
+
+// PublisherPreview builds P8 from the stored settings in the default
+// locale (UI-SPEC C20).
+func (s *Service) PublisherPreview(ctx context.Context) (PublisherPreview, error) {
+	db, err := s.DB(ctx)
+	if err != nil {
+		return PublisherPreview{}, err
+	}
+	settings, err := LoadSettings(db)
+	if err != nil {
+		return PublisherPreview{}, err
+	}
+	locale := s.DefaultLocale(ctx, db)
+	node := schema.PublisherNode(s.SiteURL(), s.PublisherOf(ctx, db, settings, locale), s.SiteName(ctx, settings, locale))
+	out := PublisherPreview{AllGood: s.PhraseCtx(ctx, "golem15.seo::lang.graph.all_good", nil)}
+	if node == nil {
+		return out, nil
+	}
+	raw, err := json.MarshalIndent(node, "", "  ")
+	if err != nil {
+		return PublisherPreview{}, err
+	}
+	out.JSON = string(raw)
+	rep := schema.ValidateNode(node)
+	for _, f := range rep.Findings {
+		out.Findings = append(out.Findings, s.FindingText(ctx, rep.Type, f))
+	}
+	return out, nil
+}