[Document] Proposal to contribute Chinese documentation

### Search before asking

- [x] I searched in the [issues](https://github.com/apache/paimon/issues) and found nothing similar.

### Motivation

Hello Paimon team and community,
I’m a Chinese-speaking user and developer interested in contributing to Paimon.

I noticed that the official documentation is mainly in English. To help more Chinese users better understand and use Paimon, I would like to contribute a set of Chinese documentation.

So far, I have already started some translation work and published the translated docs on my GitHub Pages site:
https://lss1231.github.io/paimon-docs-chinese/

Before starting, I would like to ask:

- Does the project already have any plans or ongoing efforts for Chinese documentation?

- Is there a preferred way or guidelines to contribute documentation translations or new docs?

- Is there a dedicated branch or folder for Chinese docs in the repository?

If no such plans exist yet, I would be happy to take the initiative and contribute.

Looking forward to your advice and feedback!

### Solution

I've already tried some work on this. And I've put the Chinese Document on my

### Anything else?

_No response_

### Are you willing to submit a PR?

- [ ] I'm willing to submit a PR!

Review the Chinese documentation already published at https://lss1231.github.io/paimon-docs-chinese/ and compare it with the project's current English documentation. Before treating this as complete, establish the project's preferred contribution method, location for translated docs, and translation scope with maintainers.

Written by the indexing model from the issue text.