Match built-in single sidebar .posts-nav-box.toc-widget/.toc-list so the
sidebar widget is filled (≥3 headings), supports multiple TOC shells, and
removes empty chrome.
Restore Zibll float dual-column shell, fix single settings DTO key mapping,
reorder article footer/actions, and match author bar, prev/next, title/body
typography, and limit-height expand UX.
Honor prevnext/authordesc/yiyan settings, multi-tax related queries with
orderby (incl. views), per-post maxheight override, and only expand content
when maxheight is enabled.
kate522