major refactoring adding vendor and customer features

docs/development/exception-handling.md

@@ -32,7 +32,7 @@ app/exceptions/
 ├── marketplace.py       # Import/marketplace exceptions
 ├── product.py           # MarketplaceProduct management exceptions
 ├── shop.py              # Shop management exceptions
-└── stock.py             # Stock management exceptions
+└── inventory.py             # Inventory management exceptions
 ```
 
 ## Core Concepts