Enhance sell log SQL query: Updated the QUERY_ADD_SELL_LOG to include a sell_timestamp field in the conflict resolution clause, ensuring accurate tracking of sell events. This change improves the logging mechanism for sales data in the database.

src/worker/sql.rs

@@ -275,7 +275,9 @@ DELETE FROM falukant_data.inventory WHERE id = $1;
 
 pub const QUERY_ADD_SELL_LOG: &str = r#"
 INSERT INTO falukant_log.sell (region_id, product_id, quantity, seller_id) VALUES ($1, $2, $3, $4)
-ON CONFLICT (region_id, product_id, seller_id) DO UPDATE SET quantity = falukant_log.sell.quantity + EXCLUDED.quantity;
+ON CONFLICT (region_id, product_id, seller_id) DO UPDATE
+SET quantity = falukant_log.sell.quantity + EXCLUDED.quantity,
+    sell_timestamp = NOW();
 "#;
 pub const QUERY_GET_ARRIVED_TRANSPORTS: &str = r#"
 SELECT