前端极简黑白重设计,并纳入客户端注册、站点设置与后台相关改动

- storefront 全站改为极简黑白配色:直角、细线分隔、卡片 hover 浅底、深色模式(跟随系统+手动切换)
- 抽出 storefront/partials/card 复用卡片
- 一并提交此前暂存的客户端注册 API、站点设置、后台页面与测试

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/Http/Requests/Admin/StoreCategoryRequest.php

@@ -17,7 +17,7 @@ class StoreCategoryRequest extends FormRequest
         return [
             'type' => ['required', Rule::in(['plugin', 'theme'])],
             'name' => ['required', 'string', 'max:64'],
-            'slug' => ['required', 'string', 'max:64', 'regex:/^[a-z0-9-]+$/'],
+            'slug' => ['required', 'string', 'max:64', 'regex:/^[\pL\pN][\pL\pN_-]*$/u'],
             'description' => ['nullable', 'string', 'max:255'],
             'sort_order' => ['nullable', 'integer'],
         ];