Add Bibliotheca Afghanica bibliography extraction benchmark

[MHindermann]

Mixed German/Arabic bibliographic extraction.

[MHindermann]

@sorinmarti: I don't get the sequence03 with multipart images to work, it seems like no image (instead of 4 images) are sent.

request_ADHOC_20251217_141755_sequence01.json
request_ADHOC_20251217_141755_sequence02.json
request_ADHOC_20251217_141755_sequence03.json
scoring.json

[MHindermann]

@sorinmarti: I don't get the sequence03 with multipart images to work, it seems like no image (instead of 4 images) are sent.

request_ADHOC_20251217_141755_sequence01.json request_ADHOC_20251217_141755_sequence02.json request_ADHOC_20251217_141755_sequence03.json scoring.json

Solved with correct flag multi_image_support = True