Add M3 error pages and the Markdown mail theme

Error pages for 401 to 503 in an error-view root appended to view.paths,
with an inline fallback when the Vite build is missing, and a mail theme
rendered from the application's scheme JSON, with opt-in header and
message components. Completes Phase 9.

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

config/livewire-material.php

@@ -91,6 +91,43 @@ return [
 
     'node' => env('MATERIAL_NODE', 'node'),
 
+    /*
+    |--------------------------------------------------------------------------
+    | Scheme data
+    |--------------------------------------------------------------------------
+    |
+    | The light and dark hexes `php artisan material:scheme` writes beside the
+    | stylesheet. The mail theme reads its colours here, and so does an error
+    | page when the build is missing; without the file both use the package's
+    | default scheme.
+    |
+    */
+
+    'scheme' => resource_path('css/material-scheme.json'),
+
+    /*
+    |--------------------------------------------------------------------------
+    | Mail
+    |--------------------------------------------------------------------------
+    |
+    | Markdown mail takes the theme when `mail.markdown.theme` (MAIL_MARKDOWN_THEME)
+    | is 'livewire-material::mail.theme'. 'components' puts this package's mail
+    | header and message after the application's own mail components — or
+    | publish them with `vendor:publish --tag=livewire-material-mail` instead.
+    | 'logo' replaces the app name in that header with an image: an absolute
+    | 'src', with 'width' and 'height' in pixels, which Outlook sizes it by.
+    |
+    */
+
+    'mail' => [
+        'components' => (bool) env('MATERIAL_MAIL_COMPONENTS', false),
+        'logo' => [
+            'src' => null,
+            'width' => null,
+            'height' => null,
+        ],
+    ],
+
     /*
     |--------------------------------------------------------------------------
     | Showcase
@@ -98,7 +135,8 @@ return [
     |
     | Every component in every variant, rendered in the application's own
     | scheme. Off unless the application runs locally. 'vite' names the entry
-    | points that import this package's CSS and JavaScript.
+    | points that import this package's CSS and JavaScript; the error pages
+    | load them too, showcase or not.
     |
     */