feat: add sb front matter

cmd/indexer/main.go

@@ -427,11 +427,20 @@ func indexProse(sugar *zap.SugaredLogger, tsClient *typesense.Client, mongoDB *r
 			content = joinParagraphs(strs)
 		}
 
-		// Build URL: KB uses /books/kb/{volume}/{slug}, others use /books/{book}/{slug}
+		// Build URL: KB uses /books/kb/{volume}/{slug}; chapter summaries map
+		// their "<lila>-<n>" slug to the chapter landing page; others use
+		// /books/{book}/{slug}.
 		var proseURL string
-		if book == "kb" {
+		switch {
+		case book == "kb":
 			proseURL = fmt.Sprintf("/books/kb/%d/%s", volume, slug)
-		} else {
+		case docType == "chapter-summary":
+			if parts := strings.SplitN(slug, "-", 2); len(parts) == 2 {
+				proseURL = fmt.Sprintf("/books/%s/%s/%s", book, parts[0], parts[1])
+			} else {
+				proseURL = fmt.Sprintf("/books/%s/%s", book, slug)
+			}
+		default:
 			proseURL = fmt.Sprintf("/books/%s/%s", book, slug)
 		}