[Doc]: update README for Vime

[CalvinXKY]

Sub-task

Docs — README and architecture overview (remaining #11 items: quickstart, per-model run guides, slime → vime migration guide).

Summary

• Rebrand README.md / README_zh.md from slime to Vime (slime-based RL framework, default vLLM rollout).
• Refresh architecture section: rollout described as vLLM + router; update imgs/arch.png.
• Trim slime-only sections (Blogs, Projects); add slime doc for upstream references.
• Add repo link (https://github.com/vllm-project/vime) and Vime citation.

Out of scope (follow-ups under #11)

• Quickstart doc updates
• Per-model run guides
• slime → vime migration guide

Test plan

• Preview README.md / README_zh.md on GitHub
• Confirm imgs/arch.png renders in Architecture Overview

[gemini-code-assist]

Code Review

This pull request rebrands the "slime" framework to "Vime" and transitions the default rollout backend from SGLang to vLLM (integrated with vllm-router). The changes include updating documentation in both English and Chinese, modifying repository links, and adjusting argument prefixes to support vLLM and router configurations. Review feedback focused on improving the technical tone and formatting of the Chinese README, specifically recommending more formal phrasing for "RL scaling" and standardizing the term "server-based".

[gemini-code-assist]

The phrasing "RL scaling 用" is a bit informal for technical documentation. It is recommended to use "面向 RL scaling 的" or "用于 RL scaling 的" to improve readability and maintain a professional tone in Chinese.

Suggested change

	**Vime** 是基于 [slime](https://github.com/THUDM/slime) 的 RL scaling 用 LLM post-training 框架。在保留 slime 训练栈与数据生成设计的同时，默认以 [**vLLM**](https://github.com/vllm-project/vllm)（配合 [vllm-router](https://github.com/vllm-project/router)）作为 rollout 后端，替代 SGLang。Vime 提供两大核心能力：
	**Vime** 是一个基于 [slime](https://github.com/THUDM/slime) 的、面向 RL scaling 的 LLM post-training 框架。在保留 slime 训练栈与数据生成设计的同时，默认以 [**vLLM**](https://github.com/vllm-project/vllm)（配合 [vllm-router](https://github.com/vllm-project/router)）作为 rollout 后端，替代 SGLang。Vime 提供两大核心能力：

[gemini-code-assist]

It is better to use a hyphen for "server-based" to follow standard technical writing conventions when using English terms in Chinese documentation.

Suggested change

	2. **灵活的数据生成**：通过自定义数据生成接口以及 server based engine，实现任意的训练数据生成流程。
	2. **灵活的数据生成**：通过自定义数据生成接口以及 server-based engine，实现任意的训练数据生成流程。