Forward class:button and class:close to the sidebar collapse and toast close buttons

[edalzell]

flux:sidebar.collapse and flux:toast render an inner <button> whose classes are hard-coded (size-10, and h-8 w-8), and class lands on the wrapper, so an app cannot enlarge those two controls. That matters for touch targets: WCAG 2.5.5 asks for 44×44 on mobile screens, and today the only way to get there is publishing the two stubs.

This forwards class:button on sidebar.collapse and class:close on toast to the inner button, the same shape as class:input and class:icon elsewhere, appended after the defaults. Nothing changes for callers that don't pass them.

Usage: <flux:sidebar.collapse class="lg:hidden" class:button="min-h-11 min-w-11" />, <flux:toast class:close="min-h-11 min-w-11" />.