[PROMOTE] dev → demo 晉升取貨碼有效期限修正

1. [FIX] 修正取貨碼有效期限固定為 24 小時的問題：時數模式與自訂日期模式互斥停用未使用欄位，避免隱藏的 expires_at 預填值覆蓋使用者設定的時數。

resources/views/admin/sales/pickup-codes/index.blade.php

@@ -330,6 +330,7 @@ transition-all duration-300",
                                 <div class="flex items-center gap-6 mb-6">
                                     <div class="flex-1 relative">
                                         <input type="range" name="expires_hours" x-model="expiresHours" min="1" max="168"
+                                            :disabled="expiryMode !== 'hours'"
                                             class="w-full h-1.5 bg-slate-200 dark:bg-slate-700/50 rounded-lg appearance-none cursor-pointer accent-cyan-500">
                                     </div>
                                     <div class="shrink-0 w-24 py-3 bg-white dark:bg-slate-900 rounded-2xl border border-slate-200 dark:border-slate-700 shadow-sm text-center">
@@ -351,7 +352,8 @@ transition-all duration-300",
                             <div x-show="expiryMode === 'date'" x-transition>
                                 <div class="relative group mb-6">
                                     <input type="text" name="expires_at" x-model="customExpiry"
-                                        x-init="const fp = flatpickr($el, { 
+                                        :disabled="expiryMode !== 'date'"
+                                        x-init="const fp = flatpickr($el, {
                                             enableTime: true, 
                                             dateFormat: 'Y-m-d H:i', 
                                             time_24hr: true,