feat(device): add continuous scanning support to ScanApi

- Update `ScanApi` to parse the `continuous` parameter from API requests.
- Update `DiminaActivity` and `scanCodeHandler` to pass the `continuous` flag.
- Replace `AsyncResult` with `NoneResult` in `ScanApi` since results are now handled via the callback.
- Update `ScanCodeActivity` to implement the UI and logic required for continuous scanning mode.

fix: add missing camera-camera2 dependency for CameraX