Let the admin choose one of eight colour profiles

Indigo (the default), Blue, Teal, Green, Amber, Rose and Violet in the
Vibrant style and Graphite in the Neutral style are generated from
config into the stylesheet. Admin settings opens with a colour profile
card: a swatch previews the profile on the page, and Save Settings
stores it as color_profile, which AppServiceProvider hands to the
package's resolver, so every page, mail and error page wears it. An
unknown profile is refused, and a saved one that disappears falls back
to indigo.

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

resources/views/livewire/admin/admin-settings.blade.php

@@ -2,6 +2,10 @@
     <h1 class="mb-6 type-headline-md">{{ __('System Settings') }}</h1>
 
     <form wire:submit="saveSettings" class="grid gap-6">
+        <x-card :title="__('Colour profile')" variant="outlined">
+            <x-scheme-picker wire:model="colorProfile" :hint="__('Choosing one previews it here. After saving, every page, mail and error page uses it.')" data-test="color-profile" />
+        </x-card>
+
         <x-card :title="__('Branding')" variant="outlined">
             <div class="grid gap-5">
                 <x-input wire:model="siteTitle" :label="__('Site Title')" :hint="__('Displayed as the heading on the upload page.')" />
@@ -99,7 +103,7 @@
             />
         </x-card>
 
-        <x-button type="submit" :label="__('Save Settings')" variant="filled" icon="check" spinner="saveSettings" class="w-full" />
+        <x-button type="submit" :label="__('Save Settings')" variant="filled" icon="check" spinner="saveSettings" class="w-full" data-test="save-settings" />
     </form>
 
     <x-modal wire:model="confirmingLogoRemoval" :title="__('Remove the logo?')" icon="delete">