perf(popup): use server-returned notifications after mark-repo-as-read

Have markRepoAsRead return the updated notifications list instead of
requiring a separate GET_STATE round-trip. Eliminates redundant
manual DOM removal + full re-render cycle. Fall back to GET_STATE
if the response payload is invalid.

Author: euxx

src/background/service-worker.js

@@ -750,7 +750,7 @@ async function markRepoAsRead(owner, repo) {
     await storage.setNotifications(updated);
     await updateBadge(updated.length, hasMoreNotifications);
 
-    return { success: true };
+    return { success: true, notifications: updated };
   } catch (error) {
     console.error('Failed to mark repo as read:', error);
     return { success: false, error: error.message };

src/popup/popup.js

@@ -858,21 +858,18 @@ async function handleMarkRepoAsRead(repoFullName) {
     if (response.success) {
       // Wait for stagger animation to finish before removing DOM
       await anim.waitForCompletion();
-      allElements.forEach((el) => el.remove());
 
-      const remainingItems = notificationsList.querySelectorAll('.notification-item');
-      if (remainingItems.length === 0) {
-        emptyState.hidden = false;
-        markAllBtn.disabled = true;
-      }
-
-      // Reload to get updated state
-      try {
+      // Re-render with updated notifications returned by the background.
+      // Defensive fallback: if payload shape is unexpected, reload full state.
+      let nextNotifications = response.notifications;
+      if (!Array.isArray(nextNotifications)) {
+        console.warn('MARK_REPO_AS_READ returned invalid notifications payload, reloading state');
         const state = await sendMessage(MESSAGE_TYPES.GET_STATE);
-        renderNotifications(state.notifications, true);
-      } catch (error) {
-        console.error('Failed to reload notifications:', error);
+        nextNotifications = Array.isArray(state.notifications) ? state.notifications : [];
       }
+
+      clearNotificationCache();
+      renderNotifications(nextNotifications, false);
     } else {
       anim.rollback();
       console.error('Failed to mark repo as read:', response.error);

tests/service-worker.test.js

@@ -512,7 +512,10 @@ describe('service-worker', () => {
         { id: '456', repository: { full_name: 'other/repo' }, title: 'Test 2' },
       ]);
       expect(mockAction.setBadgeText).toHaveBeenCalledWith({ text: '1' });
-      expect(sendResponse).toHaveBeenCalledWith({ success: true });
+      expect(sendResponse).toHaveBeenCalledWith({
+        success: true,
+        notifications: [{ id: '456', repository: { full_name: 'other/repo' }, title: 'Test 2' }],
+      });
     });
 
     it('should return error on API failure', async () => {
@@ -552,7 +555,10 @@ describe('service-worker', () => {
       await new Promise((resolve) => setTimeout(resolve, 50));
 
       expect(mockAction.setBadgeText).toHaveBeenCalledWith({ text: '1+' });
-      expect(sendResponse).toHaveBeenCalledWith({ success: true });
+      expect(sendResponse).toHaveBeenCalledWith({
+        success: true,
+        notifications: [{ id: '456', repository: { full_name: 'other/repo' }, title: 'Test 2' }],
+      });
     });
   });