refactor(qr): streamline barcode scanner implementation

- Remove legacy QR code processing with web workers
- Simplify camera permission handling and initialization
- Improve error handling and state management
- Update to use MLKit Barcode Scanner API consistently
- Fix type safety issues with error handling
- Remove unused camera and worker-related code
- Consolidate scanning logic into cleaner methods

The changes focus on using the native MLKit scanner capabilities
instead of the previous web worker implementation, resulting in
more reliable QR code scanning and better error handling.

ios/App/Podfile

@@ -12,6 +12,12 @@ def capacitor_pods
   pod 'Capacitor', :path => '../../node_modules/@capacitor/ios'
   pod 'CapacitorCordova', :path => '../../node_modules/@capacitor/ios'
   pod 'CapacitorApp', :path => '../../node_modules/@capacitor/app'
+  pod 'CapacitorCamera', :path => '../../node_modules/@capacitor/camera'
+  pod 'CapacitorClipboard', :path => '../../node_modules/@capacitor/clipboard'
+  pod 'CapacitorFilesystem', :path => '../../node_modules/@capacitor/filesystem'
+  pod 'CapacitorShare', :path => '../../node_modules/@capacitor/share'
+  pod 'CapawesomeCapacitorFilePicker', :path => '../../node_modules/@capawesome/capacitor-file-picker'
+  pod 'CapacitorMlkitBarcodeScanning', :path => '../../node_modules/@capacitor-mlkit/barcode-scanning'
 end
 
 target 'App' do