docs: add Chinese translation (README.zh.md)

[JasonYeYuhe]

Docs: Add Chinese translation (README.zh.md)

This PR adds a comprehensive Simplified Chinese translation of the README.md to help the Chinese-speaking community better understand and contribute to the Engram project.

Changes

• Created README.zh.md with full parity to the original English documentation.
  • Sections translated: Introduction, Architecture, Evaluation (Scaling Law, Pre-training, Long-context), Case Study, Quick Start, License, and Contact.
• Updated README.md to include a language switcher at the top for better accessibility.

Translation Strategy

• Maintained standard technical terminology (e.g., "sparsity" -> 稀疏性, "offloading" -> 卸载, "iso-parameter" -> 等参数).
  • Ensured all mathematical notation and internal links are preserved correctly.
  • Strictly followed the structural layout of the original English document.

Verification

• Verified all links (internal and external) in the translated document.
  • Ensured images and badges render correctly.
  • Checked Markdown formatting for consistency.

[Copilot]

Pull request overview

Adds a Simplified Chinese translation of the project README and exposes a language switcher so readers can easily navigate between English and Chinese documentation.

Changes:

• Added README.zh.md as a Simplified Chinese translation of the main README.
• Updated README.md to include a top-of-file language switcher linking to README.zh.md.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
README.zh.md	Introduces the Chinese README content mirroring the English structure and links.
README.md	Adds a language switcher linking to the Chinese translation.

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[Copilot]

The alt text for the case study image still says "Long Context Results", which is misleading for screen readers and when the image can’t be loaded. Please update the alt attribute to describe the case study figure (e.g., "Engram Case Study" / "Case Study").

Suggested change

	<img width="80%" src="figures/case.png" alt="Long Context Results">
	<img width="80%" src="figures/case.png" alt="Engram Case Study">