Adding a New Dataset / DataModule

anomalib splits data support into two layers per source, both under src/anomalib/data/:

• datasets/image/<name>.py — a torch-facing AnomalibDataset subclass (one dataset = one split).
• datamodules/image/<name>.py — a Lightning-facing AnomalibDataModule subclass that owns train/val/test dataloaders and split logic.

(Use datasets/video/ and datamodules/video/, or depth/, for other modalities — the patterns are similar, but base classes and split behavior differ by modality.)

Base classes to implement against