feat: daily vani

internal/repository/vani_repo.go

@@ -87,6 +87,22 @@ func (r *VaniRepo) Insert(ctx context.Context, pick *model.VaniPick) error {
 	return nil
 }
 
+// BookTitle resolves a book code to its display title (from book_meta.data.title),
+// or "" if unknown. Used to label a prose pick with its book name.
+func (r *VaniRepo) BookTitle(ctx context.Context, book string) string {
+	var raw bson.M
+	if err := r.mongo.Collection("book_meta").
+		FindOne(ctx, bson.D{{Key: "book", Value: book}}).Decode(&raw); err != nil {
+		return ""
+	}
+	if data, ok := raw["data"].(bson.M); ok {
+		if t, ok := data["title"].(string); ok {
+			return t
+		}
+	}
+	return ""
+}
+
 // --- Mongo: random candidate sampling ---
 
 // excludeIDs turns hex _id strings into a $nin ObjectID array.