feat: add localized README (Russian, Hebrew)

[chernistry]

Summary

RightLayout's core user base includes Russian and Hebrew speakers — the two non-English languages currently supported. Yet the README is English-only. Adding localized READMEs in Russian and Hebrew makes the project more welcoming and discoverable for these communities.

Why This Matters

• Russian and Hebrew speakers are the PRIMARY users of RightLayout (it solves their problem)
• Non-English speakers are more likely to contribute if docs are in their language
• Localized READMEs improve SEO — people searching in Russian/Hebrew can find the project
• Shows respect for the community and lowers the barrier to adoption
• This is a common pattern in successful open-source projects (Vue.js, FastAPI, etc.)

Files to Create

README.ru.md — Russian

Translate the full README into Russian, including:

• Project description and value proposition
• Installation instructions
• Usage guide
• How to contribute
• License

Russian-specific additions:

• Explain the Russian ↔ English layout problem (everyone in Russia knows this pain)
• Use Russian keyboard layout examples in the demo section

README.he.md — Hebrew

Translate the full README into Hebrew, including:

• Same sections as Russian
• RTL formatting considerations (GitHub renders RTL markdown)

Hebrew-specific additions:

• Explain the Hebrew ↔ English layout problem
• Note RTL-specific features

Update main README.md

Add a language selector at the top:

🌐 [English](README.md) | [Русский](README.ru.md) | [עברית](README.he.md)

Guidelines for Translators

• Don't machine-translate — we need natural, native-sounding text
• Adapt examples to be culturally relevant (don't just transliterate English examples)
• Keep technical terms in English where that's standard practice (e.g., "open source", "pull request")
• Keep the same structure as the English README for easy maintenance
• Add a note at the bottom: "This translation corresponds to README.md as of [commit hash]"

Good First Issue

This is marked as a good first issue because:

• No code changes required
• Native speakers can contribute without Swift knowledge
• Clear scope: translate one file
• Reviewable: other native speakers can review the translation

Acceptance Criteria

• README.ru.md created with full Russian translation
• README.he.md created with full Hebrew translation
• Main README.md updated with language selector links
• Translations are natural and accurate (not machine-translated)
• Technical accuracy maintained (installation steps still correct)
• RTL formatting works correctly in README.he.md