Support idle primary device warning alert from server

ts/components/ServerAlerts.tsx

@@ -0,0 +1,63 @@
+// Copyright 2025 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import React from 'react';
+import {
+  getServerAlertToShow,
+  ServerAlert,
+  type ServerAlertsType,
+} from '../util/handleServerAlerts';
+import type { WidthBreakpoint } from './_util';
+import type { LocalizerType } from '../types/I18N';
+import { CriticalIdlePrimaryDeviceDialog } from './CriticalIdlePrimaryDeviceDialog';
+import { strictAssert } from '../util/assert';
+import { WarningIdlePrimaryDeviceDialog } from './WarningIdlePrimaryDeviceDialog';
+
+export function getServerAlertDialog(
+  alerts: ServerAlertsType | undefined,
+  dialogProps: {
+    containerWidthBreakpoint: WidthBreakpoint;
+    i18n: LocalizerType;
+  }
+): JSX.Element | null {
+  if (!alerts) {
+    return null;
+  }
+  const alertToShow = getServerAlertToShow(alerts);
+  if (!alertToShow) {
+    return null;
+  }
+
+  if (alertToShow === ServerAlert.CRITICAL_IDLE_PRIMARY_DEVICE) {
+    return <CriticalIdlePrimaryDeviceDialog {...dialogProps} />;
+  }
+
+  if (alertToShow === ServerAlert.IDLE_PRIMARY_DEVICE) {
+    const alert = alerts[ServerAlert.IDLE_PRIMARY_DEVICE];
+    strictAssert(alert, 'alert must exist');
+
+    // Only allow dismissing it once
+    const isDismissable = alert.dismissedAt == null;
+
+    return (
+      <WarningIdlePrimaryDeviceDialog
+        {...dialogProps}
+        handleClose={
+          isDismissable
+            ? async () => {
+                await window.storage.put('serverAlerts', {
+                  ...alerts,
+                  [ServerAlert.IDLE_PRIMARY_DEVICE]: {
+                    ...alert,
+                    dismissedAt: Date.now(),
+                  },
+                });
+              }
+            : undefined
+        }
+      />
+    );
+  }
+
+  return null;
+}