feat: show loading state on Langfuse test connection button

client/src/components/Nav/SettingsTabs/Integrations/LangfuseConnection.tsx

@@ -1,5 +1,13 @@
 import { useState, useEffect } from 'react';
-import { Button, Input, Label, SecretInput, Switch, useToastContext } from '@librechat/client';
+import {
+  Button,
+  Input,
+  Label,
+  SecretInput,
+  Spinner,
+  Switch,
+  useToastContext,
+} from '@librechat/client';
 import {
   useGetLangfuseConnectionQuery,
   useUpdateLangfuseConnectionMutation,
@@ -162,7 +170,14 @@ export default function LangfuseConnection() {
           disabled={!canSubmit || testMutation.isLoading}
           onClick={handleTest}
         >
-          {localize('com_ui_langfuse_test')}
+          {testMutation.isLoading ? (
+            <span className="flex items-center gap-2">
+              <Spinner className="h-4 w-4" />
+              {localize('com_ui_langfuse_testing')}
+            </span>
+          ) : (
+            localize('com_ui_langfuse_test')
+          )}
         </Button>
         <Button disabled={!canSubmit || updateMutation.isLoading} onClick={handleSave}>
           {localize('com_ui_save')}

client/src/locales/en/translation.json

@@ -1650,6 +1650,7 @@
   "com_ui_langfuse_secret_key_hint": "The secret key is encrypted at rest and is never shown again after saving.",
   "com_ui_langfuse_secret_key_fingerprint": "Configured key fingerprint:",
   "com_ui_langfuse_test": "Test connection",
+  "com_ui_langfuse_testing": "Testing connection",
   "com_ui_langfuse_saved": "Langfuse connection saved",
   "com_ui_langfuse_save_error": "Failed to save the Langfuse connection",
   "com_ui_langfuse_test_success": "Connected to Langfuse successfully",