Add Clear button to notification bell dropdown

- Add notifications_cleared_at column to users table
- Clear button marks notifications as seen without deleting history
- Badge and dropdown only show notifications after last clear
- History page still shows all notifications

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/src/index.ts

@@ -122,6 +122,9 @@ async function runMigrations() {
         IF NOT EXISTS (SELECT 1 FROM information_schema.columns WHERE table_name = 'users' AND column_name = 'ai_verification_enabled') THEN
           ALTER TABLE users ADD COLUMN ai_verification_enabled BOOLEAN DEFAULT false;
         END IF;
+        IF NOT EXISTS (SELECT 1 FROM information_schema.columns WHERE table_name = 'users' AND column_name = 'notifications_cleared_at') THEN
+          ALTER TABLE users ADD COLUMN notifications_cleared_at TIMESTAMP;
+        END IF;
       END $$;
     `);
 

backend/src/models/index.ts

@@ -856,28 +856,41 @@ export const notificationHistoryQueries = {
     return result.rows;
   },
 
-  // Get recent notifications (for bell dropdown)
+  // Get recent notifications (for bell dropdown) - respects cleared_at
   getRecent: async (userId: number, limit: number = 10): Promise<NotificationHistory[]> => {
     const result = await pool.query(
-      `SELECT * FROM notification_history
-       WHERE user_id = $1
-       ORDER BY triggered_at DESC
+      `SELECT nh.* FROM notification_history nh
+       JOIN users u ON u.id = nh.user_id
+       WHERE nh.user_id = $1
+         AND (u.notifications_cleared_at IS NULL OR nh.triggered_at > u.notifications_cleared_at)
+       ORDER BY nh.triggered_at DESC
        LIMIT $2`,
       [userId, limit]
     );
     return result.rows;
   },
 
-  // Count notifications in last 24 hours (for badge)
+  // Count notifications since last clear (for badge)
   countRecent: async (userId: number, hours: number = 24): Promise<number> => {
     const result = await pool.query(
-      `SELECT COUNT(*) FROM notification_history
-       WHERE user_id = $1 AND triggered_at > NOW() - INTERVAL '1 hour' * $2`,
+      `SELECT COUNT(*) FROM notification_history nh
+       JOIN users u ON u.id = nh.user_id
+       WHERE nh.user_id = $1
+         AND nh.triggered_at > NOW() - INTERVAL '1 hour' * $2
+         AND (u.notifications_cleared_at IS NULL OR nh.triggered_at > u.notifications_cleared_at)`,
       [userId, hours]
     );
     return parseInt(result.rows[0].count, 10);
   },
 
+  // Clear notifications (sets timestamp, doesn't delete)
+  clear: async (userId: number): Promise<void> => {
+    await pool.query(
+      `UPDATE users SET notifications_cleared_at = NOW() WHERE id = $1`,
+      [userId]
+    );
+  },
+
   // Get total count for pagination
   getTotalCount: async (userId: number): Promise<number> => {
     const result = await pool.query(

backend/src/routes/notifications.ts

@@ -69,4 +69,16 @@ router.get('/count', async (req: AuthRequest, res: Response) => {
   }
 });
 
+// Clear notifications (marks as seen, doesn't delete history)
+router.post('/clear', async (req: AuthRequest, res: Response) => {
+  try {
+    const userId = req.userId!;
+    await notificationHistoryQueries.clear(userId);
+    res.json({ message: 'Notifications cleared' });
+  } catch (error) {
+    console.error('Error clearing notifications:', error);
+    res.status(500).json({ error: 'Failed to clear notifications' });
+  }
+});
+
 export default router;