Reorganize splits: move Remove360 scenes/class_03 to test, drop synthetic negatives from test; update card

Add crop-shift negatives (759 pairs total); reorganize scenes; update card

Add challenging split (swaps/replacements/rearrangements); update card

Add driv2 collection: 5 training scenes + test_shay_01 (77 pairs, 35 negatives); update card

Reorganize: backyard split into 3 scenes, test split by collection, test_backyard held out

Add michal_1 test scene (17 pairs); update card test stats

Restructure into training/{DeTaken,Remove360_based} + test split; add DeTaken photos

Add 22 no-change negative pairs; update dataset card

Add Something's Missing Here dataset (124 Remove360-based pairs)

initial commit