feat(offline): persisted query cache + unreachable banner (web + mobile) (#70)

* feat(offline): persisted query cache + unreachable banner (web + mobile)

- Web: PersistQueryClientProvider on localStorage (24h maxAge); mobile:
  AsyncStorage persister (7d). Both exclude high-churn keys (logs,
  notifications, metrics) — stale tails are worse than none.
- networkMode 'offlineFirst' so cached data serves while the refetch
  attempt fails.
- Web: ConnectivityBanner in PlatformShell pings public /health every
  15s + listens to online/offline events — slim "last-known data" bar
  so persisted state can't masquerade as live.
- Mobile: same banner in the tabs layout — /health ping plus
  expo-network's local signal distinguishes "no connection" from
  "instance down".

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* feat(mobile): cron jobs screen — schedules, run-now, execution history

- /service/cron lists the service's jobs with schedule, timezone,
  last/next run, and last status; "Run now" triggers via the existing
  POST /cron-jobs/:id/trigger and "History" expands recent executions
  with status + output/error.
- Manage row on the service detail + Stack registration.

Verified live: created */5 job on a running service, triggered it —
execution recorded with status success and captured stdout.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

---------

Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

app/frontend/src/main.tsx

@@ -1,6 +1,8 @@
 import { StrictMode } from 'react';
 import { createRoot } from 'react-dom/client';
-import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import { QueryClient } from '@tanstack/react-query';
+import { PersistQueryClientProvider } from '@tanstack/react-query-persist-client';
+import { createSyncStoragePersister } from '@tanstack/query-sync-storage-persister';
 import { BrowserRouter } from 'react-router-dom';
 import App from './app/App';
 import { ToastProvider } from './shared/components';
@@ -12,18 +14,49 @@ const queryClient = new QueryClient({
       staleTime: 30_000,
       retry: 1,
       refetchOnWindowFocus: false,
+      // Serve the persisted snapshot while offline instead of erroring.
+      networkMode: 'offlineFirst',
     },
   },
 });
 
+// High-churn or bulky keys never hit localStorage — a stale log tail is
+// worse than none.
+const NEVER_PERSIST = new Set([
+  'shell-notifications',
+  'notifications',
+  'service-logs',
+  'logs',
+  'activity',
+  'audit-logs',
+  'audit',
+  'metrics',
+  'connectivity',
+]);
+
+const persister = createSyncStoragePersister({
+  storage: window.localStorage,
+  key: 'containr-query-cache-v1',
+});
+
 createRoot(document.getElementById('root')!).render(
   <StrictMode>
-    <QueryClientProvider client={queryClient}>
+    <PersistQueryClientProvider
+      client={queryClient}
+      persistOptions={{
+        persister,
+        maxAge: 24 * 60 * 60 * 1000,
+        dehydrateOptions: {
+          shouldDehydrateQuery: (q) =>
+            q.state.status === 'success' && !NEVER_PERSIST.has(String(q.queryKey[0])),
+        },
+      }}
+    >
       <BrowserRouter>
         <ToastProvider>
           <App />
         </ToastProvider>
       </BrowserRouter>
-    </QueryClientProvider>
+    </PersistQueryClientProvider>
   </StrictMode>,
 );