[codex] Refresh Russian admin localization

[DrMaks22]

Summary

• Refresh the Russian admin/web localization on top of current main.
• Preserve the earlier ru.json work from [codex] update Russian admin localization #2027 and bring en/ru admin locale parity to 893/893 keys.
• Localize the visible chat right-sidebar/model-settings UI that was still hardcoded in English: Model/Profile tabs, Active Profile/Model, Temperature/Max Tokens/Top P/Top K/Min P, penalties, Thinking controls, prompt profile controls, live generation statuses, and bottom stats labels.
• Add English fallback merging for partial locale files so newer keys do not render as raw key names in locales that have not caught up yet.
• Add regression tests for chat model-settings i18n coverage and locale fallback behavior.

This supersedes the older #2027 PR, recreated from current main so it is easier to review in the current queue.

Validation

• JSON validation passed for all admin i18n files
• en/ru admin locale parity: 893/893 keys
• Missing/extra keys: 0
• Placeholder mismatches: 0
• Targeted hardcoded chat/model-settings English check: 0 hits
• Jinja chat template load: passed
• git diff --check: passed
• Targeted pytest: 56 passed

[jundot]

Thanks for the update. Main has changed quite a bit since this branch was created, so ru.json now conflicts with newer localization work. I’m sorry for the extra churn, but could you rebase onto current main, preserve the newer locale keys, and rerun the locale normalization and targeted i18n tests? The localization changes themselves look good.

[DrMaks22]

Thanks for the heads-up. I rebased this branch onto current main (34e9e98), resolved the ru.json conflict by keeping the newer 957-key schema, and preserved the newer locale keys from main.

I also translated the new context benchmark / prefill priority ru keys that were added while this PR was stale, then ran the repo locale normalization script:

• python3 scripts/normalize_i18n.py

Validation after the rebase/normalization:

• All admin locale files are normalized to 957/957 keys
• Missing keys: 0 for every locale
• Extra keys: 0 for every locale
• Placeholder mismatches: 0 for every locale
• en/ru strict parity: 957/957, no missing/extra keys, no placeholder mismatches
• JSON validation passed for every admin i18n file
• Jinja chat template load passed
• Targeted hardcoded chat/model-settings English check: 0 hits
• Targeted pytest: 75 passed
• git diff --check passed

I force-pushed the rebased branch. GitHub CI has restarted and is currently pending/queued.

[jundot]

Thanks for rebasing this. I verified the English fallback merge, 957-key locale and placeholder parity, and the localized chat settings and status paths against current main. The targeted chat and i18n tests pass on the combined tree. LGTM, merging.