chore: add banner

Author: wiseaidev

README.md

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 # ✨ 𝕏-AI
 
 ![Version](https://img.shields.io/crates/v/x_ai)
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 ![Last Commit](https://img.shields.io/github/last-commit/opensass/x-ai)
 ![Docs](https://img.shields.io/docsrs/x_ai)
 
+![banner](https://github.com/user-attachments/assets/7b420bc7-fcfe-4aa6-b79a-6dfe1a2c019b)
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 > **𝕏-AI** is a **complete SDK** and a WIP **CLI/TUI** that provides a powerful and intuitive interface to interact with the [**X-AI API**](https://docs.x.ai/api/).
 
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