Introduces a new Settings screen with language picker, contact/feedback button,
and logout functionality. All UI strings now use centralized string resources
with translations for English, Chinese, Spanish, Hindi, Arabic, Portuguese,
Bengali, Russian, Japanese, French, German, Korean, Italian, Turkish,
Vietnamese, Polish, Ukrainian, Dutch, Thai, and Indonesian.
Uses AppCompatDelegate for runtime locale switching without app restart.
Also adds CLAUDE.md for Claude Code guidance.
