Add the Material 3 Expressive foundation

Colour, shape, type, elevation and motion as tokens and Tailwind
utilities; `php artisan material:scheme`, which generates an app's colour
roles with Google's material-color-utilities (spec 2025); the theme head
script with light, dark and system and its Alpine store; Google Sans Flex;
every Material Symbol (4,135, outlined and filled) drawn by <x-icon>
without blade-icons; all 35 M3 Expressive shapes, ported from androidx, as
<x-shape>; the x-figure directive; the Toasts concern; DesignGuard for
applications' tests; and a showcase with every token, both themes side by
side and an icon search.

Colour utilities are `@theme inline`, so a section with its own
data-theme repaints; without it they resolve once on :root.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V9NnLxnPp8vaaurb3Z1MFy

resources/css/tokens/font.css

@@ -0,0 +1,18 @@
+/*
+ * Google Sans Flex (SIL Open Font License 1.1, resources/fonts/google-sans-flex/OFL.txt).
+ *
+ * One variable woff2, cut down with fontTools: Latin and Latin Extended plus a handful of
+ * symbols (≈ →), weight 400–700 and roundness 0–100 kept, width, grade, slant and optical
+ * size pinned — 63 KB where the full font is 4 MB. Vite copies it into the application's
+ * build from this relative url.
+ *
+ * An application that wants another typeface overrides `--md-ref-typeface-brand` (and so
+ * `font-sans`) after importing material.css.
+ */
+@font-face {
+    font-family: 'Google Sans Flex';
+    src: url('../../fonts/google-sans-flex/GoogleSansFlex-Latin.woff2') format('woff2');
+    font-weight: 400 700;
+    font-style: normal;
+    font-display: swap;
+}