- Add 19 integration tests for i18n API routes with 100% coverage
- Fix Express route ordering: specific routes (/detect) before parameterized routes (/:locale)
- Test all endpoints: locale translations, available locales, locale detection
- Test error cases: unsupported locales, missing translations, malformed headers
- Test HTTP caching headers and content-type validation
- Include i18n routes in coverage collection (was previously excluded)
Coverage improvement: 147 tests total (+19), 79.9% statements (+1.2%)
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
