Adds a single string resource to support YallaClient's upcoming
"subtitle under language-selection title" UX improvement. Translations
cover all active locales (uz-Latin, uz-Cyrillic/be, ru, en, default).

Purely additive — no code changes, no API surface impact, no BCV shift.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>