feat: add Belarusian (be) translation

[pavel-miniutka]

Description

This PR adds official Belarusian translation support to CronMaster.

Changes

• Added app/_translations/be.json with complete Belarusian translations
• All UI strings have been translated accurately
• Translation structure matches the English template

Testing

• Tested with LOCALE=be environment variable
• Verified all pages and components display correctly (Note: The translation was compared with the Italian version. There are a number of common issues: many lines are not included in the localization; the majority of the translations on the 404 page do not work in either version.)
• No broken translations or missing keys

Checklist

• Translation is complete (all keys translated)
• No JSON syntax errors
• Follows translation guidelines
• Tested in development environment
• Commit message follows conventional format

[fccview]

Thank you!
This will be part of the next release!

Merged!