fix: error boundary wrap in Layout.Content for padding, move offline banner to page top

- errorBoundary: replace Card with Layout.Content (padding: 24) to match
  the 403/exception page style, since ErrorBoundary renders outside
  ProLayout's Layout.Content
- offlineBanner: move back to rootContainer (above ProLayout) to display
  at page top as a full-width banner, restore `banner` prop

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/app.tsx

@@ -152,7 +152,6 @@ export const layout: RunTimeLayoutConfig = ({
       // if (initialState?.loading) return <PageLoading />;
       return (
         <>
-          <OfflineBanner />
           {children}
           <SettingDrawer
             disableUrlParams
@@ -190,5 +189,10 @@ export const request: RequestConfig = {
 };
 
 export function rootContainer(container: React.ReactNode) {
-  return <ErrorBoundary>{container}</ErrorBoundary>;
+  return (
+    <>
+      <OfflineBanner />
+      <ErrorBoundary>{container}</ErrorBoundary>
+    </>
+  );
 }

src/components/ErrorBoundary/index.tsx

@@ -1,5 +1,5 @@
 import { getIntl } from '@umijs/max';
-import { Button, Card, Result } from 'antd';
+import { Button, Layout, Result } from 'antd';
 import React from 'react';
 
 function isChunkLoadError(error: Error): boolean {
@@ -27,7 +27,7 @@ function renderErrorFallback(
   const isChunkError = isChunkLoadError(error);
 
   return (
-    <Card variant="borderless">
+    <Layout.Content style={{ padding: 24 }}>
       <Result
         status="error"
         title={intl.formatMessage({
@@ -60,7 +60,7 @@ function renderErrorFallback(
           </Button>,
         ]}
       />
-    </Card>
+    </Layout.Content>
   );
 }
 

src/components/OfflineBanner/index.tsx

@@ -23,9 +23,8 @@ const OfflineBanner: React.FC = () => {
   return (
     <Alert
       type="warning"
-      showIcon
+      banner
       closable={false}
-      style={{ marginBottom: 16 }}
       message={getIntl().formatMessage({
         id: 'app.network.offline',
         defaultMessage: