Add QR code scanning functionality with new QRScanner component

- Introduced a new QRScanner component to facilitate QR code scanning within the application.
- Integrated QR code scanning capabilities into the SendDialog.vue, allowing users to scan QR codes for payment destinations.
- Updated package.json and package-lock.json to include the qr-scanner library for QR code processing.
- Enhanced user experience by providing visual feedback and error handling during the scanning process.

These changes improve the payment workflow by enabling users to easily scan QR codes for transactions.

package.json

@@ -31,6 +31,7 @@
     "lucide-vue-next": "^0.474.0",
     "nostr-tools": "^2.10.4",
     "pinia": "^2.3.1",
+    "qr-scanner": "^1.4.2",
     "qrcode": "^1.5.4",
     "radix-vue": "^1.9.13",
     "reka-ui": "^2.5.0",