Patch release. A single layout fix, fully backward-compatible.

Fixed

<x-wirekit::app-shell> now reflows its main content when a collapsible sidebar collapses to its icon rail. The shell's sidebar column was a fixed 16rem, so when the nested <x-wirekit::sidebar collapsible> shrank to its 3.5rem rail the main content kept its left offset and a ~12.5rem gap appeared. On desktop the column now tracks the sidebar's width — following the --wk-sidebar-w variable when expanded and shrinking to the rail width when the sidebar is collapsed — so the content reclaims the freed space. Mobile (the off-canvas overlay) is unchanged.