feat: automatically remove items from stock when empty (quantity <= 0)

test.js

@@ -76,15 +76,25 @@ console.log('Testing absolute set (100g remaining)...');
 const updatedAbs = db.adjustQuantity(newItem.id, { newQuantity: 100 });
 assert.strictEqual(updatedAbs.quantity, 100);
 
-// Consume remaining
-console.log('Testing consume all...');
+// Consume remaining -> should automatically remove from stock
+console.log('Testing consume all (auto-remove on empty)...');
 const finished = db.adjustQuantity(newItem.id, { newQuantity: 0 });
 assert.strictEqual(finished.quantity, 0);
+assert.strictEqual(finished.deleted, true, 'Result should indicate item was deleted');
+assert.strictEqual(db.getItemById(newItem.id), undefined, 'Item should be automatically removed from DB when empty');
 
-// Delete test item
-const deleted = db.deleteItem(newItem.id);
-assert.strictEqual(deleted, true);
-assert.strictEqual(db.getItemById(newItem.id), undefined);
+// Test packet removal to 0 -> should automatically remove from stock
+console.log('Testing packet removal to 0 (auto-remove on empty)...');
+const autoRemovePack = db.createItem({
+  name: 'Test Packet Auto-Remove',
+  quantity: 250,
+  initial_quantity: 250,
+  unit: 'g'
+});
+const packFinished = db.removePacket(autoRemovePack.id, 1);
+assert.strictEqual(packFinished.quantity, 0);
+assert.strictEqual(packFinished.deleted, true);
+assert.strictEqual(db.getItemById(autoRemovePack.id), undefined, 'Packet should be automatically removed when 0 left');
 
 // Test stats
 const stats = db.getStats();