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.

CHAT_INTEGRATION.md

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+# Nostr Chat Integration for Web-App
+
+This document describes the Nostr chat integration that allows LNBits users to chat with each other using Nostr relays.
+
+## Overview
+
+The chat system integrates with the LNBits user system and Nostr relays to provide encrypted messaging between users. Each user has a Nostr keypair (stored in `pubkey` and `prvkey` fields) that enables secure communication.
+
+## Components
+
+### 1. ChatComponent.vue
+**Location**: `src/components/nostr/ChatComponent.vue`
+
+A Vue component that provides the chat interface with:
+- Peer list populated from LNBits users
+- Real-time messaging using Nostr relays
+- Encrypted message exchange
+- Connection status indicators
+
+### 2. useNostrChat.ts
+**Location**: `src/composables/useNostrChat.ts`
+
+A composable that handles:
+- Nostr relay connections
+- Message encryption/decryption
+- User authentication with LNBits
+- Real-time message subscription
+
+### 3. ChatPage.vue
+**Location**: `src/pages/ChatPage.vue`
+
+A page that integrates the chat component into the web-app.
+
+## API Endpoints
+
+### Get Current User
+```bash
+GET /users/api/v1/user/me
+Authorization: Bearer <admin_token>
+
+Response:
+{
+  "id": "user_id",
+  "username": "username",
+  "email": "email@example.com",
+  "pubkey": "nostr_public_key",
+  "prvkey": "nostr_private_key",
+  "created_at": "2024-01-01T00:00:00Z",
+  "updated_at": "2024-01-01T00:00:00Z"
+}
+```
+
+### Get All User Public Keys
+```bash
+GET /users/api/v1/nostr/pubkeys
+Authorization: Bearer <admin_token>
+
+Response:
+[
+  {
+    "user_id": "user_id",
+    "username": "username",
+    "pubkey": "nostr_public_key"
+  }
+]
+```
+
+## Features
+
+### 1. User Integration
+- Automatically loads peers from LNBits user database
+- Uses existing `pubkey` and `prvkey` fields
+- Admin-only access to private keys for messaging
+
+### 2. Nostr Relay Integration
+- Connects to multiple Nostr relays for redundancy
+- Real-time message delivery
+- Encrypted end-to-end messaging
+
+### 3. UI Features
+- Peer list with user avatars and names
+- Real-time message display
+- Connection status indicators
+- Message timestamps
+- Auto-scroll to latest messages
+
+## Security
+
+1. **Encryption**: All messages are encrypted using NIP-04 (Nostr encrypted direct messages)
+2. **Private Key Access**: Only admin users can access private keys for messaging
+3. **Relay Security**: Messages are distributed across multiple relays for redundancy
+4. **User Authentication**: Requires LNBits authentication to access chat
+
+## Setup Requirements
+
+1. **NostrTools**: The web-app needs NostrTools loaded globally
+2. **Admin Access**: Users need admin privileges to access private keys
+3. **Relay Configuration**: Default relays are configured in the composable
+4. **LNBits Integration**: Requires the updated LNBits API endpoints
+
+## Usage
+
+1. Navigate to `/chat` in the web-app
+2. The system will automatically load peers from LNBits
+3. Select a peer to start chatting
+4. Messages are encrypted and sent via Nostr relays
+
+## Configuration
+
+### Default Relays
+The system connects to these relays by default:
+- `wss://nostr.atitlan.io`
+- `wss://relay.damus.io`
+- `wss://nos.lol`
+
+### Relay Configuration
+You can modify the relays in `useNostrChat.ts`:
+```typescript
+const DEFAULT_RELAYS: NostrRelayConfig[] = [
+  { url: 'wss://your-relay.com', read: true, write: true }
+]
+```
+
+## Future Enhancements
+
+1. **Message Persistence**: Store messages locally for offline access
+2. **File Sharing**: Support for encrypted file sharing
+3. **Group Chats**: Multi-user encrypted conversations
+4. **Message Search**: Search through conversation history
+5. **Push Notifications**: Real-time notifications for new messages
+6. **Profile Integration**: Display user profiles and avatars
+7. **Message Reactions**: Support for message reactions and replies
+
+## Troubleshooting
+
+### Common Issues
+
+1. **Connection Failed**: Check relay availability and network connectivity
+2. **Messages Not Sending**: Verify user has admin privileges and private key access
+3. **Peers Not Loading**: Check LNBits API endpoint and authentication
+4. **Encryption Errors**: Ensure NostrTools is properly loaded
+
+### Debug Information
+
+The chat component logs detailed information to the console:
+- Connection status
+- Message encryption/decryption
+- Relay connection attempts
+- API call results
+
+## Dependencies
+
+- **NostrTools**: For Nostr protocol implementation
+- **Vue 3**: For reactive UI components
+- **LNBits API**: For user management and authentication
+- **Nostr Relays**: For message distribution