[FEAT] 實作機台廣告管理模組與多語系支援

1. 新增廣告管理列表與機台配置介面，包含多語系 (zh_TW, en, ja) 與完整 CRUD
2. 實作基於 Alpine 的廣告素材預覽輪播功能
3. 優化廣告素材下拉選單，強制綁定所屬公司以達成多租戶資料隔離
4. 重構廣告配置中廣告影片的縮圖渲染邏輯，移除 <video> 標籤以大幅提升頁面載入速度與節省頻寬
5. 放寬個人檔案頭像上傳限制，支援 WebP 格式

resources/views/admin/ads/partials/assign-modal.blade.php

@@ -0,0 +1,85 @@
+<div x-show="isAssignModalOpen" 
+     class="fixed inset-0 z-[100] overflow-y-auto" 
+     x-cloak
+     x-transition:enter="transition ease-out duration-300"
+     x-transition:enter-start="opacity-0"
+     x-transition:enter-end="opacity-100"
+     x-transition:leave="transition ease-in duration-200"
+     x-transition:leave-start="opacity-100"
+     x-transition:leave-end="opacity-0">
+    
+    <div class="fixed inset-0 bg-slate-900/60 backdrop-blur-sm"></div>
+
+    <div class="flex items-center justify-center min-h-screen p-4">
+        <div class="relative w-full max-w-lg bg-white dark:bg-slate-900 rounded-[2rem] shadow-2xl border border-slate-200 dark:border-white/10 overflow-visible animate-luxury-in"
+             @click.away="isAssignModalOpen = false">
+            
+            <!-- Modal Header -->
+            <div class="bg-slate-50/50 dark:bg-slate-800/50 rounded-t-[2rem] px-8 py-6 border-b border-slate-100 dark:border-white/5 flex items-center justify-between">
+                <div>
+                    <h3 class="text-xl font-black text-slate-800 dark:text-white uppercase tracking-tight">{{ __('Assign Advertisement') }}</h3>
+                    <p class="text-[10px] font-bold text-slate-400 uppercase tracking-widest mt-1">{{ __('Select a material to play on this machine') }}</p>
+                </div>
+                <button @click="isAssignModalOpen = false" class="p-2 text-slate-400 hover:text-cyan-500 transition-colors">
+                    <svg class="size-6" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" d="M6 18L18 6M6 6l12 12" /></svg>
+                </button>
+            </div>
+
+            <form @submit.prevent="submitAssignment" class="p-8 space-y-6">
+                <!-- Machine & Position Info (Read-only) -->
+                <div class="grid grid-cols-2 gap-4">
+                    <div class="p-4 bg-slate-50 dark:bg-slate-800/50 rounded-2xl border border-slate-100 dark:border-white/5">
+                        <p class="text-[10px] font-black text-slate-400 uppercase tracking-widest mb-1">{{ __('Target Position') }}</p>
+                        <p class="text-sm font-black text-cyan-600 dark:text-cyan-400 uppercase tracking-tight" x-text="{ vending: '{{ __('vending') }}', visit_gift: '{{ __('visit_gift') }}', standby: '{{ __('standby') }}' }[assignForm.position] || assignForm.position"></p>
+                    </div>
+                </div>
+
+                <!-- Ad Material Selection -->
+                <div class="space-y-2">
+                    <label class="text-xs font-black text-slate-500 dark:text-slate-400 uppercase tracking-widest ml-1">{{ __('Select Material') }}</label>
+                    <div id="assign_ad_select_wrapper">
+                        <!-- Select dropdown will be dynamically built by updateAssignSelect() based on machine company context -->
+                    </div>
+                </div>
+
+
+                <!-- Action Footer -->
+                <div class="flex items-center justify-end gap-3 pt-6">
+                    <button type="button" @click="isAssignModalOpen = false" class="px-6 py-3 text-sm font-black text-slate-500 hover:text-slate-700 dark:hover:text-slate-300 transition-colors uppercase tracking-widest">
+                        {{ __('Cancel') }}
+                    </button>
+                    <button type="submit" class="btn-luxury-primary px-10 py-3">
+                        {{ __('Confirm Assignment') }}
+                    </button>
+                </div>
+            </form>
+        </div>
+    </div>
+</div>
+
+<script>
+    // Note: This logic is added to the main adManager data object in index.blade.php
+    // Here we just define the submit handler
+    async function submitAssignment() {
+        try {
+            const response = await fetch(this.urls.assign, {
+                method: 'POST',
+                headers: {
+                    'Content-Type': 'application/json',
+                    'X-CSRF-TOKEN': '{{ csrf_token() }}'
+                },
+                body: JSON.stringify(this.assignForm)
+            });
+            const result = await response.json();
+            if (result.success) {
+                this.isAssignModalOpen = false;
+                this.fetchMachineAds();
+                window.showToast?.(result.message, 'success');
+            } else {
+                window.showToast?.(result.message || 'Error', 'error');
+            }
+        } catch (e) {
+            console.error('Failed to assign ad', e);
+        }
+    }
+</script>