[STYLE] 移除導覽列中無功能的搜尋圖示

1. 移除 resources/views/layouts/admin.blade.php 中 mobile 版與 desktop 版的搜尋圖示預留區塊。
2. 優化頂部導覽列視覺，減少冗餘的 UI 元件。

resources/views/layouts/admin.blade.php

@@ -72,19 +72,6 @@
             </div>
 
             <div class="w-full flex items-center justify-end ml-auto sm:gap-x-3 sm:order-3">
-                <!-- Mobile Search Toggle -->
-                <div class="sm:hidden">
-                    <button type="button" class="inline-flex flex-shrink-0 justify-center items-center gap-2 h-[2.375rem] w-[2.375rem] rounded-full font-medium bg-white text-gray-700 align-middle hover:bg-gray-50 focus:outline-none focus:ring-2 focus:ring-gray-400 focus:ring-offset-2 focus:ring-offset-white transition-all text-xs dark:bg-gray-800 dark:hover:bg-slate-800 dark:text-gray-400 dark:hover:text-white dark:focus:ring-gray-700 dark:focus:ring-offset-gray-800">
-                        <svg class="w-3.5 h-3.5" xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" viewBox="0 0 16 16">
-                            <path d="M11.742 10.344a6.5 6.5 0 1 0-1.397 1.398h-.001c.03.04.062.078.098.115l3.85 3.85a1 1 0 0 0 1.415-1.414l-3.85-3.85a1.007 1.007 0 0 0-.115-.1zM12 6.5a5.5 5.5 0 1 1-11 0 5.5 5.5 0 0 1 11 0z"/>
-                        </svg>
-                    </button>
-                </div>
-
-                <!-- Desktop Search Placeholder -->
-                <div class="hidden sm:block flex-1 max-w-sm">
-                    <!-- Search Input (Optional) -->
-                </div>
 
                 <div class="flex flex-row items-center justify-end gap-x-1.5 sm:gap-x-3">
                     <!-- Language Switcher -->