✨ feat(ui): add incremental-add feedback & translations for model lists (#1218)

Front-end enhancements around “Add custom models”:

• EditChannel.js / EditTagModal.js
  – Skip models that already exist instead of blocking the action.
  – Collect actually inserted items and display:
      • Success toast: “Added N models: model1, model2 …”
      • Info toast when no new model detected.
  – Keeps UX smooth while preserving deduplication logic.

• i18n
  – en.json: added keys
      • "已新增 {{count}} 个模型：{{list}}"
      • "未发现新增模型"
  – Fixed a broken JSON string containing smart quotes to maintain valid syntax.

Result:
Users can bulk-paste model names; duplicates are silently ignored and the UI clearly lists what was incrementally appended. All messages are fully internationalised.

Closes #1218

web/src/i18n/locales/en.json

@@ -1652,5 +1652,7 @@
   "开启后，仅“消费”和“错误”日志将记录您的客户端 IP 地址": "After enabling, only \"consumption\" and \"error\" logs will record your client IP address",
   "只有当用户设置开启IP记录时，才会进行请求和错误类型日志的IP记录": "Only when the user sets IP recording, the IP recording of request and error type logs will be performed",
   "设置保存成功": "Settings saved successfully",
-  "设置保存失败": "Settings save failed"
+  "设置保存失败": "Settings save failed",
+  "已新增 {{count}} 个模型：{{list}}": "Added {{count}} models: {{list}}",
+  "未发现新增模型": "No new models were added"
 }