feat: add edit item details dialog with warehouse stock validation

- Create EditItemDialog component with two-column layout for editing item quantity, UOM, rate, warehouse, and discount
- Add custom quantity counter with inline minus/plus buttons
- Implement warehouse fetching API endpoint to get all warehouses for company
- Add real-time stock validation when changing warehouse with toast notifications
- Disable update button when insufficient stock or out of stock
- Integrate with posCart store updateItemDetails action
- Add edit button to InvoiceCart for each item
- Use custom Toast component for stock notifications

Author: Ahmed Osama

POS/components.d.ts

@@ -14,6 +14,7 @@ declare module 'vue' {
     CreateCustomerDialog: typeof import('./src/components/sale/CreateCustomerDialog.vue')['default']
     CustomerDialog: typeof import('./src/components/sale/CustomerDialog.vue')['default']
     DraftInvoicesDialog: typeof import('./src/components/sale/DraftInvoicesDialog.vue')['default']
+    EditItemDialog: typeof import('./src/components/sale/EditItemDialog.vue')['default']
     InvoiceCart: typeof import('./src/components/sale/InvoiceCart.vue')['default']
     InvoiceHistoryDialog: typeof import('./src/components/sale/InvoiceHistoryDialog.vue')['default']
     ItemSelectionDialog: typeof import('./src/components/sale/ItemSelectionDialog.vue')['default']