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/shape.css

@@ -0,0 +1,21 @@
+/*
+ * Shape, as M3's corner scale.
+ *
+ * Values from @material/web's token files (Apache-2.0, © Google LLC). `full` is a large
+ * length rather than @material/web's `50cqmin`, which resolves against a container an
+ * application may never declare.
+ *
+ * As utilities: rounded-corner-xs … rounded-corner-full.
+ */
+:root {
+    --md-sys-shape-corner-none: 0px;
+    --md-sys-shape-corner-xs: 4px;
+    --md-sys-shape-corner-sm: 8px;
+    --md-sys-shape-corner-md: 12px;
+    --md-sys-shape-corner-lg: 16px;
+    --md-sys-shape-corner-lg-increased: 20px;
+    --md-sys-shape-corner-xl: 28px;
+    --md-sys-shape-corner-xl-increased: 32px;
+    --md-sys-shape-corner-xxl: 48px;
+    --md-sys-shape-corner-full: 9999px;
+}