feat: add settings table and backup notification functionality

src/lib/init-db.js

@@ -500,5 +500,19 @@ export default function initializeDatabase() {
 		CREATE INDEX IF NOT EXISTS idx_notifications_user_read ON notifications(user_id, is_read);
 		CREATE INDEX IF NOT EXISTS idx_notifications_created ON notifications(created_at);
 		CREATE INDEX IF NOT EXISTS idx_notifications_type ON notifications(type);
+
+		-- Settings table for application configuration
+		CREATE TABLE IF NOT EXISTS settings (
+			key TEXT PRIMARY KEY,
+			value TEXT NOT NULL,
+			description TEXT,
+			updated_at TEXT DEFAULT CURRENT_TIMESTAMP,
+			updated_by TEXT,
+			FOREIGN KEY (updated_by) REFERENCES users(id)
+		);
+
+		-- Insert default settings
+		INSERT OR IGNORE INTO settings (key, value, description) VALUES 
+		('backup_notification_user_id', '', 'User ID to receive backup completion notifications');
 	`);
 }