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/CreateStoreDialog.vue

@@ -269,6 +269,7 @@ 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
@@ -342,8 +343,11 @@ const loadAvailableZones = async () => {
   const currentUser = auth.currentUser?.value
   if (!currentUser?.wallets?.length) return
   
+  const inkey = paymentService.getPreferredWalletInvoiceKey()
+  if (!inkey) return
+
   try {
-    const zones = await nostrmarketAPI.getZones(currentUser.wallets[0].inkey)
+    const zones = await nostrmarketAPI.getZones(inkey)
     availableZones.value = zones
     
     // Auto-select the first available zone to make form valid
@@ -370,9 +374,14 @@ const addNewZone = async () => {
     return
   }
 
+  const adminKey = paymentService.getPreferredWalletAdminKey()
+  if (!adminKey) {
+    throw new Error('No wallet admin key available')
+  }
+
   try {
     const createdZone = await nostrmarketAPI.createZone(
-      currentUser.wallets[0].adminkey,
+      adminKey,
       {
         name: newZone.name!,
         currency: values.currency!,
@@ -418,9 +427,14 @@ const createStore = async (formData: any) => {
       selectedZones.includes(zone.id)
     )
 
+    const wallet = paymentService.getPreferredWallet()
+    if (!wallet) {
+      throw new Error('No wallet available')
+    }
+
     const stallData: CreateStallRequest = {
       name,
-      wallet: currentUser.wallets[0].id,
+      wallet: wallet.id,
       currency,
       shipping_zones: selectedZoneData,
       config: {
@@ -428,8 +442,13 @@ const createStore = async (formData: any) => {
       }
     }
 
+    const adminKey = paymentService.getPreferredWalletAdminKey()
+    if (!adminKey) {
+      throw new Error('No wallet admin key available')
+    }
+
     const newStall = await nostrmarketAPI.createStall(
-      currentUser.wallets[0].adminkey,
+      adminKey,
       stallData
     )