Remove MendeleyCXR (no longer part of the FleXray evaluation) and update README

splits README: paper results are scored on test, val used only for development

Card: FluXray now ships in this repo; licenses listed per folder

Add FluXray 1.0 (label-exact synthetic radiographs) under FluXray/

Redistribute BTXRD (CC BY 4.0, figshare 27865398) in the fxr-dataset format

Add per-dataset split assignments and quality-control exclusions

MendeleyCXR: Montgomery + Shenzhen subsets (704 samples)

MendeleyCXR: remove folder before re-upload without the Darwin subset

MendeleyCXR: remove Darwin-subset files (3000/11984)

MendeleyCXR: remove Darwin-subset files (2000/11984)

MendeleyCXR: remove Darwin-subset files (1000/11984)

Dataset card: describe FluXray inline

Dataset card: describe the FluXray companion release files

MendeleyCXR: drop the Darwin subset (duplicates DarwinCVD19); keep Montgomery + Shenzhen (704 samples)

refine dataset citation and availability notes

update links and citation guidance

MendeleyCXR: credit upstream sources in LICENSE

MendeleyCXR: credit upstream sources in README.md

Add FleXray data release: 7 repackaged X-ray sources + MURA forearm/humerus annotations

initial commit