feat(ui): 渠道表单模型标签和映射输入框显示平台对应颜色

- PricingEntryCard 折叠态模型 tag 按平台着色
- ModelTagInput 模型标签按平台着色
- 模型映射输入框边框按平台着色

frontend/src/views/admin/ChannelsView.vue

@@ -322,6 +322,7 @@
                     :value="srcModel"
                     type="text"
                     class="input flex-1 text-xs"
+                    :class="getPlatformInputBorder(section.platform)"
                     :placeholder="t('admin.channels.form.mappingSource', 'Source model')"
                     @change="renameMappingKey(sIdx, srcModel, ($event.target as HTMLInputElement).value)"
                   />
@@ -330,6 +331,7 @@
                     :value="section.model_mapping[srcModel]"
                     type="text"
                     class="input flex-1 text-xs"
+                    :class="getPlatformInputBorder(section.platform)"
                     :placeholder="t('admin.channels.form.mappingTarget', 'Target model')"
                     @input="section.model_mapping[srcModel] = ($event.target as HTMLInputElement).value"
                   />
@@ -363,6 +365,7 @@
                   v-for="(entry, idx) in section.model_pricing"
                   :key="idx"
                   :entry="entry"
+                  :platform="section.platform"
                   @update="updatePricingEntry(sIdx, idx, $event)"
                   @remove="removePricingEntry(sIdx, idx)"
                 />
@@ -532,6 +535,17 @@ function getRateBadgeClass(platform: string): string {
   }
 }
 
+function getPlatformInputBorder(platform: string): string {
+  switch (platform) {
+    case 'anthropic': return 'border-orange-300 focus:border-orange-500 dark:border-orange-700'
+    case 'openai': return 'border-emerald-300 focus:border-emerald-500 dark:border-emerald-700'
+    case 'gemini': return 'border-blue-300 focus:border-blue-500 dark:border-blue-700'
+    case 'antigravity': return 'border-purple-300 focus:border-purple-500 dark:border-purple-700'
+    case 'sora': return 'border-rose-300 focus:border-rose-500 dark:border-rose-700'
+    default: return ''
+  }
+}
+
 // ── Helpers ──
 function formatDate(value: string): string {
   if (!value) return '-'