fix: HTML sitemap headings follow each locale until an editor sets one

Settings > Sitemaps no longer prefills a content type's heading with its
label in the administrator's language, so a save that did not touch the
heading stores none and each locale's HTML sitemap keeps the label
translated into it. The field's comment says so.

extensions_settings.go

@@ -80,6 +80,7 @@ func typeSettingsDocument(types []pact.MenuItemType) ([]byte, error) {
 			}},
 			yaml.MapItem{Key: base + "title", Value: yaml.MapSlice{
 				{Key: "label", Value: "golem15.sitemap::lang.settings.type_title"},
+				{Key: "comment", Value: "golem15.sitemap::lang.settings.type_title_comment"},
 				{Key: "type", Value: "mltext"},
 				{Key: "span", Value: "full"},
 				{Key: "tab", Value: TabTypes},
@@ -118,17 +119,18 @@ func (p *Plugin) typeSettingsTab(types []pact.MenuItemType) *pact.AdminFormExten
 			if err != nil {
 				return nil, err
 			}
-			def := p.defaultLocale(ctx, in.DB)
-			tr := p.translator()
 			out := map[string]any{}
 			for _, typ := range types {
 				cfg := classes.EffectiveType(typ, rows)
 				base := classes.TypeFieldBase(typ.Key)
 				out[base+"include"] = cfg.Include
 				out[base+"slug"] = cfg.Slug
+				// Only stored headings (L2 WR-05): a type without one loads
+				// empty, so a save that did not touch it stores none and each
+				// locale's HTML sitemap keeps the label translated into it.
 				titles := cfg.Titles
-				if len(titles) == 0 {
-					titles = map[string]string{def: controllers.Phrase(ctx, tr, typ.Label, nil)}
+				if titles == nil {
+					titles = map[string]string{}
 				}
 				out[base+"title"] = titles
 			}