Align single-post layout/visuals with Zibll: fix sidebar-over-content float geometry (position:unset, 311px token, kill Bootstrap/container padding and the 280px sidebar override), demote theme-box to spacing- only, unify breadcrumb/cover/graphic utilities, and split aksrt-single render helpers under the file-size limit.
Wire settings-driven sidebar visibility and body site-layout classes, replace content-layout CSS grid with Zibll float geometry, move sidebar DOM to content-wrap sibling across single/archive/page/home, and add post meta show_layout overrides.
kate522