Two related fixes for `'layouts::app'` style references (used by
arkhe.admin.layout default config) :

1. Register 'layouts' as a regular view namespace via loadViewsFrom().
   Blade::anonymousComponentPath only adds a *hashed* prefix to the view
   finder — fine for the component compiler (<x-layouts::app>) but not
   for ViewFactory lookups (view('layouts::app'), used by Livewire
   HandlesPageComponents). Without the namespace, Laravel throws
   "No hint path defined for [layouts]".

2. Add resources/views/layouts/app.blade.php as a dispatcher between
   app/sidebar (default) and app/header variants — same pattern as the
   already-present layouts/auth.blade.php dispatcher. Without it,
   view('layouts::app') had no file to resolve to.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>