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/js/tabs.js

@@ -29,18 +29,18 @@ document.addEventListener('alpine:init', () => {
             }
 
             if (focus) {
-                this.$refs.bar.querySelector(`[data-tab="${CSS.escape(name)}"]`)?.focus()
+                this.$refs.bar.querySelector(`[data-md-tab="${CSS.escape(name)}"]`)?.focus()
             }
         },
 
         step(by) {
             const tabs = this.tabs()
             const rtl = getComputedStyle(this.$refs.bar).direction === 'rtl'
-            const at = tabs.findIndex((tab) => tab.dataset.tab === this.selected)
+            const at = tabs.findIndex((tab) => tab.dataset.mdTab === this.selected)
             const next = tabs[(at + (rtl ? -by : by) + tabs.length) % tabs.length]
 
             if (next) {
-                this.choose(next.dataset.tab, true)
+                this.choose(next.dataset.mdTab, true)
             }
         },
 
@@ -49,7 +49,7 @@ document.addEventListener('alpine:init', () => {
             const tab = last ? tabs.at(-1) : tabs[0]
 
             if (tab) {
-                this.choose(tab.dataset.tab, true)
+                this.choose(tab.dataset.mdTab, true)
             }
         },
     }))