Add Russian translation

[ewgen198409]

What does this implement/fix?

Adds the Russian translation file (ru.json) — a complete translation of all 1372 UI strings covering the dashboard, device editor, wizard, settings, firmware jobs, secrets, authentication, and all other sections.

Related issue or feature (if applicable):

Types of changes

• Bugfix (non-breaking change which fixes an issue) — bugfix
• New feature (non-breaking change which adds functionality) — new-feature
• Enhancement to an existing feature — enhancement
• Breaking change (fix or feature that would cause existing functionality to not work as expected) — breaking-change
• Refactor (no behaviour change) — refactor
• Documentation only — docs
• Maintenance / chore — maintenance
• CI / workflow change — ci
• Dependencies bump — dependencies

Checklist

• The code change is tested and works locally.
• npm run lint passes.
• npm run test passes (4 pre-existing failures in open-logs.test.ts unrelated to this change).
• Tests have been added to verify that the new code works (where applicable).

[marcelveldt]

I'm sorry but translations are managed by Lokalize: https://github.com/esphome/device-builder-frontend#thanks-to-lokalise

I don't think we can merge the translations directly.

[bdraco]

Thanks for the PR. Would you please send these to Lokalise instead?

https://developers.esphome.io/contributing/translations/