chore(ci): add multiple language support for translation-changelog

[nevermarine]

Description

This PR adds bidirectional translation support to the translate-changelog action. The action now supports translating changelog files between English and Russian in both directions (en->ru and ru->en), with configurable file naming patterns.

Key technical changes:

• Added source_lang and target_lang inputs to specify translation direction
• Added file_prefix input for customizable file naming (e.g., CHANGELOG-v or v)
• Added github_token input for PR creation authentication
• Implemented YAML-aware translation that preserves structure and only translates values (keys remain in English)
• Implemented smart branch management: creates or reuses translation branches
• Added force push support to update existing translations when source files change

Why do we need it, and what problem does it solve?

Previously, the action only supported Russian->English translation with hardcoded file patterns. This created several limitations:

1. One-way translation only: Users who write changelogs in English couldn't translate to Russian
2. Inflexible file naming: The v*.yml pattern was hardcoded, couldn't work with different naming conventions like CHANGELOG-v*.yml
3. Poor translation quality: Line-by-line translation was breaking YAML structure and translating keys like features: into функции:

This update enables:

• Bidirectional translation workflows (write in either language, translate to the other)
• Support for different repository file naming conventions
• Proper YAML structure preservation with semantic translation

What is the expected result?

For Russian->English translation (default behavior):

- uses: your-org/translate-changelog@main
  with:
    github_token: ${{ secrets.GITHUB_TOKEN }}

For English->Russian translation:

- uses: your-org/translate-changelog@main
  with:
    github_token: ${{ secrets.GITHUB_TOKEN }}
    source_lang: en
    target_lang: ru
    file_prefix: CHANGELOG-v

Expected results:

1. When a changelog file matching the pattern is committed, the action automatically creates a translation
2. Translation branch is named translation/{source}-to-{target}/{version} (e.g., translation/en-to-ru/v3.1.0)
3. YAML structure is preserved - only string values are translated, keys remain in English
4. A PR is created with the translated changelog
5. If the source file is updated, the translation is automatically updated (force push to the same branch)