feat: replace notification checkboxes with card-based layout (#5421)

Replace EventBusCheckboxes with card-based notification settings:
- Each event group gets its own card with responsive grid layout
- Master checkbox per group with indeterminate state
- Inline parameter inputs (CPU threshold) appear when enabled
- Theme-adaptive via Ant Design Card component

Components:
- NotificationLayout, NotificationCard, NotificationHeader, NotificationEvent
- TelegramNotifications, EmailNotifications with explicit event configs

frontend/src/components/ui/notifications/NotificationGroup.tsx

@@ -0,0 +1,60 @@
+import { Space } from 'antd';
+import { useTranslation } from 'react-i18next';
+import type { AllSetting } from '@/models/setting';
+import type { NotificationGroupConfig } from './types';
+import { NotificationCard } from './NotificationCard';
+import { NotificationHeader } from './NotificationHeader';
+import { NotificationEvent } from './NotificationEvent';
+
+interface Props {
+  config: NotificationGroupConfig;
+  selected: string[];
+  onToggle: (key: string) => void;
+  onToggleAll: (keys: string[]) => void;
+  allSetting: AllSetting;
+  updateSetting: (patch: Partial<AllSetting>) => void;
+}
+
+export function NotificationGroup({ config, selected, onToggle, onToggleAll, allSetting, updateSetting }: Props) {
+  const { t } = useTranslation();
+
+  const count = config.events.filter((e) => selected.includes(e.key)).length;
+  const total = config.events.length;
+
+  function toggleAll() {
+    const values = config.events.map((e) => e.key);
+    onToggleAll(values);
+  }
+
+  return (
+    <NotificationCard
+      icon={config.icon}
+      title={t(`pages.settings.${config.title}`)}
+      extra={
+        <NotificationHeader
+          count={count}
+          total={total}
+          allSelected={count === total}
+          indeterminate={count > 0 && count < total}
+          onToggleAll={toggleAll}
+        />
+      }
+    >
+      <Space direction="vertical" size={8} style={{ width: '100%' }}>
+        {config.events.map((event) => (
+          <NotificationEvent
+            key={event.key}
+            label={t(`pages.settings.${event.label}`)}
+            checked={selected.includes(event.key)}
+            onToggle={() => onToggle(event.key)}
+          >
+            {event.extra?.({
+              value: Number((allSetting as unknown as Record<string, unknown>)[event.settingKey]) || 0,
+              onChange: (v) => updateSetting({ [event.settingKey]: v }),
+            })}
+          </NotificationEvent>
+        ))}
+      </Space>
+    </NotificationCard>
+  );
+}