refactor: Replace Nostr chat preloader with a singleton pattern for improved state management

- Remove the useNostrChatPreloader composable and integrate its functionality into the useNostrChat composable, streamlining chat data handling.
- Update App.vue and ChatComponent to utilize the new singleton instance for managing chat connections and peer subscriptions.
- Enhance Navbar and ChatComponent to reflect changes in unread message tracking and peer management, improving user experience.
- Ensure proper error handling and logging during chat connection and peer loading processes.

src/App.vue

@@ -8,28 +8,39 @@ import { Toaster } from '@/components/ui/sonner'
 import 'vue-sonner/style.css'
 import { auth } from '@/composables/useAuth'
 import { useMarketPreloader } from '@/composables/useMarketPreloader'
-import { useNostrChatPreloader } from '@/composables/useNostrChatPreloader'
+import { nostrChat } from '@/composables/useNostrChat'
 import { toast } from 'vue-sonner'
 
 const route = useRoute()
 const showLoginDialog = ref(false)
 
-// Initialize preloaders
+// Initialize preloader
 const marketPreloader = useMarketPreloader()
-const chatPreloader = useNostrChatPreloader()
 
 // Hide navbar on login page
 const showNavbar = computed(() => {
   return route.path !== '/login'
 })
 
-function handleLoginSuccess() {
+async function handleLoginSuccess() {
   showLoginDialog.value = false
   toast.success('Welcome back!')
   
   // Trigger preloading after successful login
   marketPreloader.preloadMarket()
-  chatPreloader.preloadChat()
+  
+  // Connect to chat
+  if (!nostrChat.isConnected.value) {
+    try {
+      await nostrChat.connect()
+      
+      // Load peers and subscribe to all for notifications
+      const peers = await nostrChat.loadPeers()
+      await nostrChat.subscribeToAllPeersForNotifications(peers)
+    } catch (error) {
+      console.error('Failed to initialize chat:', error)
+    }
+  }
 }
 
 onMounted(async () => {
@@ -42,15 +53,23 @@ onMounted(async () => {
 })
 
 // Watch for authentication changes and trigger preloading
-watch(() => auth.isAuthenticated.value, (isAuthenticated) => {
+watch(() => auth.isAuthenticated.value, async (isAuthenticated) => {
   if (isAuthenticated) {
     if (!marketPreloader.isPreloaded.value) {
       console.log('User authenticated, triggering market preload...')
       marketPreloader.preloadMarket()
     }
-    if (!chatPreloader.isPreloaded.value) {
-      console.log('User authenticated, triggering chat preload...')
-      chatPreloader.preloadChat()
+    if (!nostrChat.isConnected.value) {
+      console.log('User authenticated, connecting to chat...')
+      try {
+        await nostrChat.connect()
+        
+        // Load peers and subscribe to all for notifications
+        const peers = await nostrChat.loadPeers()
+        await nostrChat.subscribeToAllPeersForNotifications(peers)
+      } catch (error) {
+        console.error('Failed to initialize chat:', error)
+      }
     }
   }
 }, { immediate: true })