feat: add Khmer language support

[YannVanneth]

Translation Proposal: Khmer (ភាសាខ្មែរ)

About This Translation

This PR adds Khmer language support to the React documentation, making React accessible to Khmer-speaking developers in Cambodia and the Cambodian diaspora.

Translation Experience

This is my first formal translation contribution to an open-source project. While I'm new to technical translation, I am:

• A native Khmer speaker with strong proficiency in English
• Passionate about making quality technical resources available to the Cambodian developer community
• Committed to learning and following best practices for technical documentation translation
• Eager to collaborate with experienced translators and maintainers to ensure high-quality output

I recognize that technical translation requires precision and consistency, and I'm dedicated to investing the time and effort needed to deliver accurate, readable translations that serve the Khmer-speaking React community well.

Proposed Maintainers

Initial Maintainer:

• @YannVanneth - Yann Vanneth
• @RinSanom - Rin Sanom
• @SivkimHENG - Heng Sivkim

I'm currently the sole maintainer proposing this translation. I'm actively seeking Khmer-speaking React developers who are interested in joining as co-maintainers.

Commitment

I'm committed to:

• Translating the React documentation accurately while maintaining technical precision
• Following the project's translation guidelines and style guide closely
• Seeking feedback and collaborating with the community to improve translation quality
• Actively maintaining and updating the translation as React evolves
• Building a community of Khmer-speaking React developers

Call for Co-Maintainers

🇰🇭 Calling all Khmer-speaking React developers! If you're interested in helping maintain this translation and making React more accessible to the Cambodian developer community, please comment below! Having multiple maintainers will ensure better quality and sustainability.

I'm also open to mentorship from experienced translation maintainers in this project.

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Note: I understand this PR may remain open until additional maintainers join to ensure sustainable long-term maintenance of the translation. I'm actively working to connect with potential co-maintainers in the Cambodian developer community.