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!