Add low stock endpoint

Distribution/Features/Stock/StockRepository.cs

@@ -41,6 +41,17 @@ public class StockRepository(AppDBContext db) : IStockRepository
             .Where(b => b.FK_ItemId == itemId)
             .ToListAsync();
 
+    public Task<List<StockBalance>> GetLowStockAsync(Guid? locationId)
+    {
+        var query = db.StockBalances
+            .Include(b => b.Item)
+            .Where(b => b.LocationType == LocationType.Warehouse
+                && b.Item.ReorderLevel != null
+                && b.Quantity < b.Item.ReorderLevel);
+        if (locationId.HasValue) query = query.Where(b => b.LocationId == locationId.Value);
+        return query.OrderBy(b => b.Quantity).ToListAsync();
+    }
+
     public async Task AddBalanceAsync(StockBalance balance) =>
         await db.StockBalances.AddAsync(balance);