Fixes an issue where device data (e.g., Presets.xml) could not be located when accessed via MAC address because the internal directory structure is organized by serial number.
- Add a `macToSerial` mapping in `DataStore` to bridge MAC addresses from API requests to internal serial-numbered directories.
- Implement automatic mapping population during `DataStore` initialization by scanning `DeviceInfo.xml` files.
- Update `AccountDeviceDir` to transparently resolve MAC addresses to serial numbers for file path construction.
- Enhance UPnP discovery to capture the MAC address (as `serialNumber` in the device description) for better device identification.
- Include automated tests for MAC-to-serial resolution and UPnP enrichment.
Tobias Gesellchen
403e2275dc