feat: add LNBits wallet plugin integration

- Introduced LNBits as a Lightning Network wallet provider for Lamassu ATMs.
- Added configuration options for LNBits in the environment variables.
- Implemented core functionalities including invoice creation, payment processing, balance monitoring, and payment status tracking.
- Created unit tests for the LNBits plugin to ensure functionality and error handling.
- Updated development environment setup to include LNBits configuration.

packages/server/lib/plugins/wallet/lnbits/README.md

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+# LNBits Wallet Plugin
+
+This plugin integrates LNBits as a Lightning Network wallet provider for Lamassu Bitcoin ATMs.
+
+## Features
+
+- **Lightning Invoice Creation**: Generate BOLT11 invoices for incoming payments
+- **Payment Processing**: Send Lightning payments to any BOLT11 invoice
+- **Balance Monitoring**: Check wallet balance in real-time
+- **Payment Status Tracking**: Monitor invoice payment status
+- **Route Probing**: Test payment feasibility before attempting
+- **Network Detection**: Automatic mainnet/testnet/regtest detection
+
+## Configuration
+
+### Required Environment Variables
+
+```bash
+LNBITS_ENDPOINT=https://your-lnbits-server.com
+LNBITS_ADMIN_KEY=your_admin_key_here
+```
+
+**Important**: The admin key is wallet-specific in LNBits. No separate walletId is needed.
+
+### Database Configuration
+
+The plugin configuration is stored in the database and can be managed through the Lamassu admin interface.
+
+## API Functions
+
+### Core Functions
+
+#### `newAddress(account, info, tx)`
+Creates a new Lightning invoice for receiving payments.
+
+**Parameters:**
+- `account`: Object containing `endpoint` and `adminKey`
+- `info`: Transaction info object
+- `tx`: Transaction object with `cryptoAtoms` and `cryptoCode`
+
+**Returns:** BOLT11 Lightning invoice string
+
+#### `getStatus(account, tx)`
+Checks the payment status of a Lightning invoice.
+
+**Parameters:**
+- `account`: Configuration object
+- `tx`: Transaction object with `toAddress` (Lightning invoice)
+
+**Returns:** Object with `status` field: 'confirmed', 'pending', or 'notSeen'
+
+#### `sendCoins(account, tx)`
+Sends a Lightning payment to a BOLT11 invoice.
+
+**Parameters:**
+- `account`: Configuration object
+- `tx`: Transaction object with `toAddress` and optional `cryptoAtoms`
+
+**Returns:** Object with `txid` and `fee`
+
+#### `balance(account, cryptoCode)`
+Gets the current wallet balance.
+
+**Parameters:**
+- `account`: Configuration object
+- `cryptoCode`: Must be 'LN'
+
+**Returns:** BigNumber balance in satoshis
+
+### Utility Functions
+
+#### `isLnInvoice(address)`
+Checks if a string is a valid Lightning invoice.
+
+#### `isLnurl(address)`
+Checks if a string is a valid LNURL.
+
+#### `probeLN(account, cryptoCode, invoice)`
+Tests payment route feasibility for different amounts.
+
+#### `cryptoNetwork(account, cryptoCode)`
+Detects network type from endpoint URL.
+
+## Error Handling
+
+The plugin provides detailed error messages for common issues:
+
+- **Configuration errors**: Missing endpoint or admin key
+- **Network errors**: Connection timeouts or unreachable server
+- **API errors**: Invalid requests or authentication failures
+- **Invoice errors**: Invalid BOLT11 format or expired invoices
+
+## Testing
+
+Run unit tests:
+```bash
+npm test -- tests/unit/test_lnbits_plugin.js
+```
+
+## Migration from Galoy
+
+This plugin replaces the Galoy (Blink) integration with the following improvements:
+
+1. **Simpler Configuration**: Only requires endpoint and admin key
+2. **RESTful API**: Easier to debug than GraphQL
+3. **Self-Hosted Option**: Can run your own LNBits instance
+4. **Better Error Messages**: More descriptive error handling
+5. **Native Webhook Support**: Real-time payment notifications (future enhancement)
+
+## Security Considerations
+
+- Store the admin key securely (marked as `secret: true` in database)
+- Use HTTPS endpoints in production
+- Validate all Lightning invoices before processing
+- Implement rate limiting for API calls (handled by LNBits)
+- Monitor wallet balance and set alerts for low balance
+
+## Troubleshooting
+
+### Common Issues
+
+1. **"LNBits configuration missing"**
+   - Ensure both `endpoint` and `adminKey` are set
+   - Check environment variables or database configuration
+
+2. **"Invalid Lightning invoice"**
+   - Verify the invoice starts with 'lnbc', 'lntb', or 'lnbcrt'
+   - Check if the invoice has expired
+
+3. **"LNBits API Error: 404"**
+   - Payment hash not found (invoice may not exist)
+   - Check if using correct endpoint URL
+
+4. **"LNBits API Error: 401"**
+   - Invalid admin key
+   - Verify the admin key is correct and has proper permissions
+
+## Support
+
+For LNBits-specific issues, refer to:
+- [LNBits Documentation](https://docs.lnbits.com)
+- [LNBits GitHub](https://github.com/lnbits/lnbits)
+
+For Lamassu integration issues, contact Lamassu support.