Update stock status calculations and add restock/overstock qty fields and calculations

inventory-server/db/metrics-schema.sql

@@ -39,6 +39,8 @@ CREATE TABLE IF NOT EXISTS product_metrics (
     weeks_of_inventory INT,
     reorder_point INT,
     safety_stock INT,
+    reorder_qty INT DEFAULT 0,
+    overstocked_amt INT DEFAULT 0,
     -- Financial metrics
     avg_margin_percent DECIMAL(10,3),
     total_revenue DECIMAL(10,3),