Add task category and GitHub link

Hi! I'm Niels from the Hugging Face community science team. This PR improves the dataset card by:
- Adding the `text-retrieval` task category to the metadata.
- Including a link to the official GitHub repository for easier access to the code and scripts.

README.md

@@ -1,5 +1,7 @@
 ---
 license: mit
+task_categories:
+- text-retrieval
 tags:
 - retrieval-augmented-generation
 - deep-research
@@ -10,6 +12,8 @@ tags:
 
 This repository provides the retrieval indexes built on the passage and document corpora of the BrowseComp-Plus dataset, as used in the paper [Revisiting Text Ranking in Deep Research](https://arxiv.org/abs/2602.21456).
 
+**Code:** [https://github.com/ChuanMeng/text-ranking-in-deep-research](https://github.com/ChuanMeng/text-ranking-in-deep-research)
+
 The released indexes correspond to the following retrievers:
 
 - [BM25](https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/okapi_trec3.pdf)