feat: Add Nostr chat integration for LNBits users

- Introduce a new chat system that allows LNBits users to communicate via Nostr relays.
- Implement ChatComponent for real-time messaging, peer selection, and message display.
- Create useNostrChat composable to manage Nostr relay connections, message encryption, and user authentication.
- Develop ChatPage to serve as the main interface for the chat feature.
- Add API endpoints for retrieving current user and public keys for peer messaging.
- Ensure secure communication with encryption and admin-only access to private keys.

src/pages/ChatPage.vue

@@ -0,0 +1,22 @@
+<template>
+  <div class="container mx-auto p-4 h-screen">
+    <div class="flex flex-col h-full">
+      <!-- Page Header -->
+      <div class="mb-4">
+        <h1 class="text-2xl font-bold">Nostr Chat</h1>
+        <p class="text-muted-foreground">
+          Chat with other LNBits users using Nostr relays
+        </p>
+      </div>
+
+      <!-- Chat Component -->
+      <div class="flex-1 border rounded-lg overflow-hidden">
+        <ChatComponent />
+      </div>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import ChatComponent from '@/components/nostr/ChatComponent.vue'
+</script>