feat: make Updates discovery atomic (Closes #753)

frontend/dashboard.js

@@ -1008,7 +1008,15 @@
 
   const updateTriageLauncher = createUpdateTriageLauncher({
     selectUpdates: () => selectMobileQueue('update'),
-    discover: () => notificationPager.loadAll(() => lastNotifications),
+    discover: () => api('api/v1/notifications/snapshot'),
+    applySnapshot: snapshot => {
+      lastNotifications = snapshot.items || [];
+      notificationPager.reset({page:1, total:snapshot.total || 0, has_more:false});
+      if (lastContextSnapshot) {
+        lastContextSnapshot.notifications = lastNotifications;
+        paintMyWork(lastContextSnapshot);
+      }
+    },
     isUpdatesSelected: () => selectedWorkFilter === 'update',
     hasMore: () => Boolean(notificationPagination.has_more),
     hasCheckpoint: () => updateTriage.resumable(),

frontend/update-triage-launcher.js

@@ -10,9 +10,14 @@
     options.announce('Checking all unread updates…');
     pending = Promise.resolve()
       .then(() => options.discover())
-      .then(complete => {
+      .then(discovery => {
         if (!options.isUpdatesSelected()) return 'cancelled';
-        if (complete === false || options.hasMore()) {
+        if (discovery === false || discovery?.complete === false) {
+          options.announce('Updates check paused. Retry to check older unread updates.');
+          return 'incomplete';
+        }
+        if (discovery?.complete) options.applySnapshot?.(discovery);
+        if (options.hasMore()) {
           options.announce('Updates check paused. Retry to check older unread updates.');
           return 'incomplete';
         }