Sweep up navigation's last data-navigation-* references

Plan step 36 (navigation group, second batch, cleanup). Every leftover
data-navigation-*, data-tall, data-hide-on-scroll, data-hidden,
data-width, data-align, data-divider, data-fill and component-level
data-open reference outside the rewritten stylesheets and views moves
to data-md-*, in the files the two component commits left alone:
tests/Feature/Components/ScaffoldTest.php (the scaffold's own rewrite
is a later batch, but it renders the bar and the rail today and asserts
their hooks); tests/Browser/NavigationTest.php, ShowcaseTest.php and
ColourProfilesTest.php (selectors only — document-level attributes,
data-rail, data-rail-auto and data-app-shell*, keep their names).
NavigationTest.php also gets the browser tests the plan owed this
group (docs/plans/material-3-browser-tests.md § Navigation): a tall
bar's vertical layout at a width where the short bar would go
horizontal; hide-on-scroll never firing while a pinned snackbar is on
screen; a narrow rail's 80px width and centred destinations; a rail
that hides when collapsed leaving the layout and coming back only
through an application's own menu button.

resources/css/components/navigation.css and its import in tailwind.css
are deleted now that nothing imports the file any more (the previous
commit's message said this already happened there; it did not — this
is where it actually lands).

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

resources/boost/skills/livewire-material-development/SKILL.md

@@ -983,7 +983,7 @@ M3 Expressive's navigation rail: collapsed (96px, icon over label) or expanded (
 
 - `mode`: `collapsed`, `expanded`, `collapsible` (default: expanded until its menu button collapses it; the choice is `$store.rail`, remembered and applied before the first paint), `modal` (collapsed in the layout; the menu button or `$store.rail.show()` opens it expanded over a scrim, focus held until Escape, the scrim or leaving the page), `adaptive` (`<x-scaffold>`'s, one rail per window size class: hidden and opened as a modal on a compact window, collapsed and opened as a modal at `medium`, a standard rail from `expanded` — collapsed there, expanded from `large`).
 - Props: `label` ("Main"), `width` (expanded width, `16rem`, held between 220 and 360px — or the word `narrow` for M3's other *collapsed* width, 80px against the default 96, where the items are their icons alone; the labels stay in the accessibility tree and a narrow rail still expands to 16rem), `align` (`top` default, or `center` for M3's centred destinations — preferred on a tablet; the menu button, brand and FAB stay at the top and the footer at the foot), `hide-when-collapsed` (M3's immersive expanded behaviour, `collapsible` and `adaptive` only: collapsing the rail takes it out of the layout instead of narrowing it, and `$store.rail.show()` brings it back expanded over a scrim — so put a menu button in the app bar; the rail's own button then docks it again. Not below `medium` for a collapsible rail nor at `medium` for an adaptive one, where the window rather than the visitor collapses it and M3's collapsed rail may never hide), `menu` (the menu button; on by default for `collapsible`, `modal`, `adaptive`), `divider` (M3's optional vertical divider on the page's side — use it when the page scrolls under a fixed rail), `fill` (`false` for a transparent container, which M3 allows while the items keep 3:1 contrast). Slots: `brand` (beside the menu button, expanded only), `header` (one `<x-fab label icon>`, which the rail morphs into an extended FAB and back as it expands — it also rests at elevation 0, as M3 asks of a nested FAB), the destinations (the only part that scrolls), `footer`. In a flex row the rail sticks to the top of the viewport.
-- Anything else inside a rail takes both shapes with the `rail-collapsed:` variant, true while that rail is drawn collapsed for whatever reason: `<span class="rail-collapsed:hidden">…expanded only…</span>`, `<span class="hidden rail-collapsed:inline-flex">…collapsed only…</span>`. Put the variant on a wrapper, never on a component. Nothing that shows while collapsed may be wider than 96px.
+- Anything else inside a rail can take both shapes by matching the rail's own state directly — `data-md-navigation-rail`'s value, `:not([data-md-open])`, and the window band each mode collapses in, the same selectors `resources/css/components/navigation-rail.css` uses for every branch of "collapsed" (that file, not this one, is where the numbers live). The Tailwind `rail-collapsed:` variant this used to teach no longer exists: the package's own CSS is plain now. Nothing that shows while collapsed may be wider than 96px.
 - A `collapsible` rail is held to the collapsed 96px below `medium` (600px), where M3 says to use a navigation bar rather than a standard rail. `collapsed` and `expanded` are fixed-width by design: wrap one in a `medium:` element if it must not show on a phone.
 - `<x-navigation-rail-item>`: the same props as `<x-navigation-bar-item>`. `<x-navigation-rail-section label="…">`: a group with a heading that shows only while the rail is expanded; it names the group for screen readers either way.
 - `$store.rail`: `collapsed`, `toggle()`, `collapse()`, `expand()` (the remembered choice; `auto` is true while nothing is stored, so an adaptive rail takes its window size class's default instead, and the first choice clears it), `open`, `show()`, `hide()` (the modal rail; closed on every `wire:navigate`). `config/livewire-material.php` → `rail.default` (`expanded` or `collapsed`) and `rail.storage_key` (`material-rail`).