Draw the tabs without Tailwind

Plan step 36 (navigation group, third and last stream): <x-tabs>'s
and <x-tab>'s class lists move into resources/css/components/tabs.css,
one commit for both since they share it. Root data-md-tabs; the bar
data-md-tabs-bar with data-md-variant/-stacked/-scrollable, holding
data-md-tab buttons (data-md-tab-content, the new data-md-tab-label
wrapping the label and badge, data-md-tab-indicator); the panel
data-md-tab-panel. The server-rendered hidden panel (N-05), the 52dp
scrollable offset (N-10), the indicator's 2dp inset (N-18), the ring
moved 2px out (N-20) and aria-current sharing the active colour
(N-21) already matched the audit; only hooks, units and layer
changed. Sizes (48/64px tab height, 90px minimum width) stay px;
spacing goes through the measurement tokens where the value matches
one (the icon-label and label-badge gaps, the panel's top padding).
Imports icon.css and badge.css for what the view renders.

Hooks renamed: data-tabs-bar, data-tab, data-tab-content,
data-tab-indicator, data-scrollable, data-stacked and the bar's
data-variant to data-md-*, updated in tabs.js (dataset.tab ->
dataset.mdTab), section-nav.blade.php (which reuses the tab bar's
hooks under its own, still-Tailwind, markup),
tests/Feature/Components/TabsTest.php and tests/Browser/BarsTest.php.

Added the owed browser test: a tab panel never flashes before Alpine
boots, read from an inline script that runs while the page is still
parsing, well before Alpine's own script (docs/plans/material-3-browser-tests.md).

This closes plan step 36: every navigation-group component is now
data-md-* and Tailwind-free; tailwind.css's Navigation block keeps
only navigation.css (the bar and rail, out of this batch's scope).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

resources/views/components/section-nav.blade.php

@@ -62,18 +62,18 @@
     @endif
 
     <nav aria-label="{{ $label }}" class="max-medium:hidden">
-        <ul data-tabs-bar data-variant="secondary" @if ($scrollable) data-scrollable @endif>
+        <ul data-md-tabs-bar data-md-variant="secondary" @if ($scrollable) data-md-scrollable @endif>
             @foreach ($items as $item)
                 @php($on = $isCurrent($item))
 
                 <li class="flex min-w-0">
                     <a
                         href="{{ $item['url'] }}"
-                        data-tab
+                        data-md-tab
                         @if ($on) aria-current="page" @endif
                         @unless ($noWireNavigate) wire:navigate @endunless
                     >
-                        <span data-tab-content>
+                        <span data-md-tab-content>
                             @isset($item['icon'])
                                 <x-livewire-material::icon :name="$item['icon']" :filled="$on" optical="20" class="size-5" />
                             @endisset
@@ -81,7 +81,7 @@
                             @if (filled($item['badge'] ?? null))
                                 <x-livewire-material::badge :value="$item['badge']" />
                             @endif
-                            <span data-tab-indicator aria-hidden="true"></span>
+                            <span data-md-tab-indicator aria-hidden="true"></span>
                         </span>
                     </a>
                 </li>