fix(ui): exit infinite spinner with a retry card on failed initial load

List pages wrapped content in <Spin spinning={!fetched}> where 'fetched' only flipped true once data arrived. With staleTime: Infinity + retry: 1, a transient network error on first load left the query in a permanent error state and the spinner stuck forever.

Now 'fetched' also settles on query.isError, and a failed load shows a Result error card with a Refresh button that self-heals when the backend returns, mirroring the existing XrayPage pattern. Applied to clients, inbounds, groups, nodes, and the dashboard.

Fixes #4723

frontend/src/pages/inbounds/InboundsPage.tsx

@@ -1,11 +1,13 @@
 import { lazy, useCallback, useEffect, useMemo, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import {
+  Button,
   Card,
   Col,
   ConfigProvider,
   Layout,
   Modal,
+  Result,
   Row,
   Spin,
   Statistic,
@@ -74,6 +76,7 @@ export default function InboundsPage() {
 
   const {
     fetched,
+    fetchError,
     dbInbounds,
     clientCount,
     onlineClients,
@@ -559,6 +562,13 @@ export default function InboundsPage() {
             <Spin spinning={!fetched} delay={200} description={t('loading')} size="large">
               {!fetched ? (
                 <div className="loading-spacer" />
+              ) : fetchError ? (
+                <Result
+                  status="error"
+                  title={t('somethingWentWrong')}
+                  subTitle={fetchError}
+                  extra={<Button type="primary" onClick={refresh}>{t('refresh')}</Button>}
+                />
               ) : (
                 <Row gutter={[isMobile ? 8 : 16, 12]}>
                   <Col span={24}>

frontend/src/pages/inbounds/useInbounds.ts

@@ -248,7 +248,9 @@ export function useInbounds() {
     if (lastOnlineQuery.data) setLastOnlineMap(lastOnlineQuery.data);
   }, [lastOnlineQuery.data]);
 
-  const fetched = slimQuery.data !== undefined && defaultsQuery.data !== undefined;
+  const fetched = (slimQuery.data !== undefined || slimQuery.isError) && (defaultsQuery.data !== undefined || defaultsQuery.isError);
+  const fetchErrorSource = slimQuery.error || defaultsQuery.error;
+  const fetchError = fetchErrorSource ? (fetchErrorSource as Error).message : '';
 
   const refresh = useCallback(async () => {
     // Invalidate at the inbounds root so both `slim` (this page's list)
@@ -373,6 +375,7 @@ export function useInbounds() {
 
   return {
     fetched,
+    fetchError,
     dbInbounds,
     clientCount,
     onlineClients,