Enhance CheckoutPage with Nostr integration for order placement

- Import and utilize the Nostr store to retrieve the user's public key for order placement.
- Implement debug logging to track authentication state and public key availability.
- Ensure that the order placement process checks for a valid Nostr public key, improving user feedback and error handling during the checkout process.

src/modules/market/views/CheckoutPage.vue

@@ -272,6 +272,7 @@
 import { ref, computed, onMounted } from 'vue'
 import { useRoute } from 'vue-router'
 import { useMarketStore } from '@/stores/market'
+import { useNostrStore } from '@/stores/nostr'
 import { injectService, SERVICE_TOKENS } from '@/core/di-container'
 import { 
   Card, 
@@ -291,6 +292,7 @@ import {
 
 const route = useRoute()
 const marketStore = useMarketStore()
+const nostrStore = useNostrStore()
 const authService = injectService(SERVICE_TOKENS.AUTH_SERVICE) as any
 
 // State
@@ -410,14 +412,29 @@ const placeOrder = async () => {
     if (!currentStall.value) {
       throw new Error('Stall information not available')
     }
-    if (!authService.isAuthenticated.value || !authService.user.value?.pubkey) {
+    // Debug logging to understand auth state
+    console.log('Auth check:', {
+      isAuthenticated: authService.isAuthenticated.value,
+      user: authService.user.value,
+      hasPubkey: !!authService.user.value?.pubkey,
+      nostrPubkey: nostrStore.account?.pubkey
+    })
+    
+    // Get pubkey from auth service or fallback to nostr store
+    const userPubkey = authService.user.value?.pubkey || nostrStore.account?.pubkey
+    
+    if (!authService.isAuthenticated.value) {
       throw new Error('You must be logged in to place an order')
     }
     
+    if (!userPubkey) {
+      throw new Error('No Nostr public key found. Please ensure your Nostr identity is configured.')
+    }
+
     // Create the order using the market store's order placement functionality
     const orderData = {
       stallId: stallId.value,
-      buyerPubkey: authService.user.value?.pubkey || '',
+      buyerPubkey: userPubkey,
       sellerPubkey: currentStall.value.pubkey,
       status: 'pending' as const,
       items: checkoutCart.value.products.map(item => ({