Mark Persona8B as a private resource

Move Persona8B out of public resources and document request-based access.

README.md

@@ -27,9 +27,14 @@ Our north star is **8.3B persona-scale simulation**—one synthetic profile per
 |---|---|
 | [MatrAIx Persona 1M Public Release](https://huggingface.co/datasets/MatrAIx2026/MatrAIx_Persona_1M_Public_Release) | Public persona records organized by real-human, extracted, and synthetic sources. |
 | [Demo Application Data](https://huggingface.co/datasets/MatrAIx2026/Demo_Application_Data) | Persona profiles for evaluation tasks across surveys, chat, web, and OS applications. |
-| [Persona8B](https://huggingface.co/datasets/MatrAIx2026/Persona8B) | Large-scale persona data from the broader MatrAIx persona space. |
 | [Existing Data](https://huggingface.co/datasets/MatrAIx2026/Existing_Data) | Supporting public data used in MatrAIx research and development. |
 
+## Private resource
+
+| Resource | Access |
+|---|---|
+| Persona8B | Large-scale persona data from the broader MatrAIx persona space. Available by request; contact [info@matraix.ai](mailto:info@matraix.ai). |
+
 ## Explore MatrAIx
 
 - GitHub: [MatrAIx-ai/MatrAIx](https://github.com/MatrAIx-ai/MatrAIx)