Some functions(__wti_page_merge_deltas_with_base_image_int, __page_unpack_deltas, __page_merge_base_internal_deltas, etc) that are intended solely for reconstructing internal pages from deltas currently contain references to leaf page logic. The goal of this ticket is to refactor those functions to remove leaf page–specific references, ensuring a clear separation of concerns and improving code clarity and maintainability for internal page delta reconstruction.