fix(inventory): refresh list, close modal, update badges after creating item

- Expose loadInventoryStats globally so inventory.js can call it after CRUD
- Fix token key: use pos_token (not access_token) to match auth scheme
- After successful POST /items: close modal, clear form inputs, reload stats
- Bump inventory.js cache-bust query param v3 -> v4

pos/static/js/inventory.js

@@ -216,6 +216,13 @@
                 }
                 document.getElementById('createResult').innerHTML = '<span style="color:var(--color-success);">' + msg + '</span>';
                 loadItems(currentPage);
+                // Close modal, clear form, refresh badges
+                closeCreateModal();
+                ['newPartNumber','newName','newBrand','newBarcode','newCost','newPrice1','newPrice2','newPrice3','newMinStock','newInitialStock','newLocation'].forEach(function(id) {
+                    var el = document.getElementById(id);
+                    if (el) el.value = '';
+                });
+                if (window.loadInventoryStats) window.loadInventoryStats();
             } else {
                 document.getElementById('createResult').innerHTML = '<span style="color:var(--color-error);">' + (result ? result.error || 'Error' : 'Error de red') + '</span>';
             }