This PR adds a dataset card for the Inst2Seg dataset, which was introduced in the paper [InstructSAM: Segment Any Instance with Any Instructions](https://huggingface.co/papers/2605.26102). The card includes:
- Metadata for the `image-segmentation` task category.
- Links to the paper and the official GitHub repository.
- A description of the dataset and the types of instructions it supports.
- Instructions on how to organize the annotation files and raw images.
- The BibTeX citation for the work.
