feat(ui): show webhook URL hint on Lark channel config

Display an info banner with the webhook endpoint path when Feishu/Lark
channel is configured in webhook mode, with a copy button for the path.

ui/web/src/i18n/locales/en/channels.json

@@ -107,7 +107,9 @@
       "noSchema": "No configuration schema for this channel type.",
       "saved": "Saved",
       "saveConfig": "Save Config",
-      "saving": "Saving..."
+      "saving": "Saving...",
+      "webhookUrlLabel": "Set this as your Lark app's Event Request URL:",
+      "copyPath": "Copy path"
     },
     "groups": {
       "saved": "Saved",

ui/web/src/i18n/locales/vi/channels.json

@@ -107,7 +107,9 @@
       "noSchema": "Không có lược đồ cấu hình cho loại channel này.",
       "saved": "Đã lưu",
       "saveConfig": "Lưu cấu hình",
-      "saving": "Đang lưu..."
+      "saving": "Đang lưu...",
+      "webhookUrlLabel": "Đặt URL này làm Event Request URL cho ứng dụng Lark:",
+      "copyPath": "Sao chép đường dẫn"
     },
     "groups": {
       "saved": "Đã lưu",

ui/web/src/i18n/locales/zh/channels.json

@@ -107,7 +107,9 @@
       "noSchema": "此Channel类型没有配置模式。",
       "saved": "已保存",
       "saveConfig": "保存配置",
-      "saving": "保存中..."
+      "saving": "保存中...",
+      "webhookUrlLabel": "将此URL设置为Lark应用的事件请求URL：",
+      "copyPath": "复制路径"
     },
     "groups": {
       "saved": "已保存",

ui/web/src/pages/channels/channel-detail/channel-config-tab.tsx

@@ -1,6 +1,6 @@
 import { useState, useCallback } from "react";
 import { useTranslation } from "react-i18next";
-import { Save, Check, AlertCircle } from "lucide-react";
+import { Save, Check, AlertCircle, Info, Copy } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import type { ChannelInstanceData } from "@/types/channel";
 import { configSchema } from "../channel-schemas";
@@ -62,6 +62,20 @@ export function ChannelConfigTab({ instance, onUpdate }: ChannelConfigTabProps)
     );
   }
 
+  // Show webhook URL hint for Feishu/Lark in webhook mode
+  const isFeishu = instance.channel_type === "feishu";
+  const connectionMode = (values.connection_mode as string) ?? "webhook";
+  const showWebhookUrl = isFeishu && connectionMode === "webhook";
+  const webhookPath = (values.webhook_path as string) || "/feishu/events";
+  const webhookUrl = `https://<your-gateway-domain>${webhookPath}`;
+
+  const [copied, setCopied] = useState(false);
+  const handleCopy = useCallback(() => {
+    navigator.clipboard.writeText(webhookPath);
+    setCopied(true);
+    setTimeout(() => setCopied(false), 2000);
+  }, [webhookPath]);
+
   return (
     <div className="max-w-2xl space-y-6">
       <ChannelFields
@@ -71,6 +85,28 @@ export function ChannelConfigTab({ instance, onUpdate }: ChannelConfigTabProps)
         idPrefix="cd-cfg"
       />
 
+      {showWebhookUrl && (
+        <div className="flex items-start gap-2 rounded-md border border-blue-200 bg-blue-50 px-3 py-2 text-sm dark:border-blue-800 dark:bg-blue-950">
+          <Info className="h-4 w-4 shrink-0 mt-0.5 text-blue-600 dark:text-blue-400" />
+          <div className="flex-1 min-w-0">
+            <p className="text-blue-800 dark:text-blue-200">{t("detail.config.webhookUrlLabel")}</p>
+            <div className="flex items-center gap-1.5 mt-1">
+              <code className="text-xs bg-blue-100 dark:bg-blue-900 px-1.5 py-0.5 rounded break-all">
+                {webhookUrl}
+              </code>
+              <button
+                type="button"
+                onClick={handleCopy}
+                className="shrink-0 text-blue-600 hover:text-blue-800 dark:text-blue-400 dark:hover:text-blue-200"
+                title={t("detail.config.copyPath")}
+              >
+                {copied ? <Check className="h-3.5 w-3.5" /> : <Copy className="h-3.5 w-3.5" />}
+              </button>
+            </div>
+          </div>
+        </div>
+      )}
+
       {saveError && (
         <div className="flex items-center gap-2 rounded-md border border-destructive/50 bg-destructive/10 px-3 py-2 text-sm text-destructive">
           <AlertCircle className="h-4 w-4 shrink-0" />