Add dashboard localization foundation

[douglasmonsky]

Summary

Builds on #27 by @HoangVung to add dashboard localization infrastructure.

This keeps the dashboard i18n work from #27, fixes dashboard regressions found during review, and refactors translations into a broader language-catalog foundation with starter locale support.

Changes

• Add external dashboard locale catalogs with English as canonical.
• Add starter locale catalogs for English, Vietnamese, Spanish, French, German, Portuguese, Japanese, Simplified Chinese, Korean, Russian, Italian, and Arabic.
• Preserve dashboard --lang and CODEX_USAGE_TRACKER_LANG support.
• Preserve dashboard language selector and browser language persistence.
• Generate language selector options from supported language metadata.
• Add catalog validation tests for key parity, placeholder parity, metadata parity, supported-language coverage, and Arabic RTL direction.
• Replace brittle English-string dynamic translation lookups with stable recommendation and flag keys where practical, while keeping backwards-compatible English fields.
• Fix expanded thread-call row rendering.
• Fix language switching so runtime live status and selected details are preserved.
• Update README, CLI reference, and dashboard guide documentation for dashboard localization and future language additions.
• Extend release and installed-package smoke checks so locale JSON resources must ship in packaged artifacts.

Validation

• node --check src/codex_usage_tracker/plugin_data/dashboard/dashboard.js
• .venv/bin/python -m compileall src/codex_usage_tracker
• .venv/bin/python -m pytest tests/test_i18n.py tests/test_recommendations.py tests/test_pricing.py
• .venv/bin/python -m pytest tests/test_cli_release.py
• .venv/bin/python -m pytest tests/test_store_dashboard_mcp.py
• .venv/bin/python -m pytest
• .venv/bin/python -m build
• .venv/bin/python -m twine check dist/*
• .venv/bin/python scripts/check_release.py --dist
• git diff --check --cached

Attribution

Based on the i18n work in #27 by @HoangVung. The branch preserves the original commits from @HoangVung and the integration commit includes Co-authored-by: hvung1982 <vungcpa@gmail.com> so attribution survives a squash merge.

[HoangVung]

Dear Mr Douglas, Many thank for your acceptance, I think the data should be integrated with common online drive services (Googld drive, Onedrive) so that, app alway have all data when changing computer, or run in other device. Vào 00:27 T.5, 11 Th6, 2026 Douglas Monsky ***@***.***> đã viết:

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