{{-- Source-of-truth for the sidebar collapsed state. localStorage is the only authority; `body.dash-sidebar-collapsed` is mirrored from it so CSS can drive the entire shell (sidebar width, content offset, label visibility) off a single class. Exposes window.dashSidebar.toggle() for the toggle button to call synchronously inside its click handler. Runs: 1. Synchronously inside on every full page load — applies the class before paint so there's no flash of the wrong width. 2. After `livewire:navigated` so wire:navigate doesn't reset it. --}}