Update notification service

AppImage/scripts/health_persistence.py

@@ -114,6 +114,22 @@ class HealthPersistence:
             )
         ''')
         
+        # Notification history table (records all sent notifications)
+        cursor.execute('''
+            CREATE TABLE IF NOT EXISTS notification_history (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                event_type TEXT NOT NULL,
+                channel TEXT NOT NULL,
+                title TEXT,
+                message TEXT,
+                severity TEXT,
+                sent_at TEXT NOT NULL,
+                success INTEGER DEFAULT 1,
+                error_message TEXT,
+                source TEXT DEFAULT 'server'
+            )
+        ''')
+        
         # Migration: add suppression_hours column to errors if not present
         cursor.execute("PRAGMA table_info(errors)")
         columns = [col[1] for col in cursor.fetchall()]
@@ -125,6 +141,8 @@ class HealthPersistence:
         cursor.execute('CREATE INDEX IF NOT EXISTS idx_category ON errors(category)')
         cursor.execute('CREATE INDEX IF NOT EXISTS idx_resolved ON errors(resolved_at)')
         cursor.execute('CREATE INDEX IF NOT EXISTS idx_events_error ON events(error_key)')
+        cursor.execute('CREATE INDEX IF NOT EXISTS idx_notif_sent_at ON notification_history(sent_at)')
+        cursor.execute('CREATE INDEX IF NOT EXISTS idx_notif_severity ON notification_history(severity)')
         
         conn.commit()
         conn.close()