Refactor wallet balance handling and integrate PaymentService for centralized management

- Replaced direct wallet balance computation in Navbar and WalletPage with a centralized totalBalance property from PaymentService, improving code maintainability.
- Updated CreateProductDialog, CreateStoreDialog, and MerchantStore components to utilize PaymentService for retrieving wallet admin and invoice keys, enhancing consistency across the application.
- These changes streamline wallet management and improve the overall architecture of the wallet module.

src/modules/market/components/CreateProductDialog.vue

@@ -232,6 +232,7 @@ const emit = defineEmits<{
 
 // Services
 const nostrmarketAPI = injectService(SERVICE_TOKENS.NOSTRMARKET_API) as NostrmarketAPI
+const paymentService = injectService(SERVICE_TOKENS.PAYMENT_SERVICE) as any
 const toast = useToast()
 
 // Local state
@@ -336,8 +337,13 @@ const updateProduct = async (formData: any) => {
       }
     }
 
+    const adminKey = paymentService.getPreferredWalletAdminKey()
+    if (!adminKey) {
+      throw new Error('No wallet admin key available')
+    }
+
     const updatedProduct = await nostrmarketAPI.updateProduct(
-      currentUser.wallets[0].adminkey,
+      adminKey,
       props.product.id,
       productData
     )
@@ -398,8 +404,13 @@ const createProduct = async (formData: any) => {
       }
     }
 
+    const adminKey = paymentService.getPreferredWalletAdminKey()
+    if (!adminKey) {
+      throw new Error('No wallet admin key available')
+    }
+
     const newProduct = await nostrmarketAPI.createProduct(
-      currentUser.wallets[0].adminkey,
+      adminKey,
       productData
     )