Windows binary crashes: ATR bytes are not JSON serializable

[SenteQuentinADACRB]

Environment

• OS: Windows
• eID reader: [reader model]
• Belgian eID middleware version: [version]
• Downloaded package: eidreader-1.0.9.zip

Steps to reproduce

1. Install eidreader.exe and register the beid:// URL protocol.
2. Ensure the handler points to the actual executable:
   C:\eidreader\eidreader\eidreader.exe
3. Insert a Belgian eID card into the reader.
4. Trigger the beid:// handler from the browser using the "Read eID card" action.

Actual result

eidreader.exe starts, detects the reader/card, then crashes with:

Failed to execute script 'eidreader' due to unhandled exception:
Object of type bytes is not JSON serializable

Traceback (most recent call last):
  File "eidreader.py", line 300, in <module>
  File "eidreader.py", line 259, in main
  File "json\__init__.py", line 235, in dumps
  File "json\encoder.py", line 202, in encode
  File "json\encoder.py", line 263, in iterencode
  File "json\encoder.py", line 182, in default
TypeError: Object of type bytes is not JSON serializable
when serializing dict item 'ATR'