Add initial Russian locale support to the OpenMAIC UI

[GRIZZZZZLY]

Summary

This PR adds initial Russian (ru-RU) locale support to the OpenMAIC UI.

Changes

• adds ru-RU to locale handling
• adds Russian to language selectors
• adds Russian translations for:
  • generation flow
  • classroom role configuration
  • settings UI
  • settings modal
  • profile UI
• adds English fallback for untranslated Russian keys

Why this matters

This makes OpenMAIC usable for Russian-speaking users and extends the current localization model beyond Chinese and English.

Notes

This is an initial localization pass, not a full translation audit. Some less frequently used UI areas may still fall back to English until follow-up cleanup is completed.

[GRIZZZZZLY]

[GRIZZZZZLY]

Hi! I fixed the formatting issues in this PR and pushed an update.\n\nThe latest workflow run now shows action_required rather than a code failure, so it looks like GitHub Actions may need maintainer approval to run for this fork PR.\n\nCould someone please approve and run the workflows for this PR? Thanks!

[wyuc]

Hey, thanks for putting this together!

Since this PR was opened, we've refactored the i18n system. Adding a new locale now only needs two changes:

1. A lib/i18n/locales/<locale>.json file with all translation keys
2. One line in lib/i18n/locales.ts to register it

See the Translation Guide and #365 (Japanese) for reference.

Could you rebase onto current main and simplify your PR to follow this pattern? The translation strings you've already done are great, it's mainly the wiring that needs updating. Happy to merge once it's aligned.

[wyuc]

Hey, thanks for putting this together!

Since this PR was opened, we've refactored the i18n system. Adding a new locale now only needs two changes:

1. A lib/i18n/locales/<locale>.json file with all translation keys
2. One line in lib/i18n/locales.ts to register it

See the Translation Guide and #365 (Japanese) for reference.

Could you rebase onto current main and simplify your PR to follow this pattern? The translation strings you've already done are great, it's mainly the wiring that needs updating. Happy to merge once it's aligned.