- Remove disruptive alert() on error pages, rely on role="alert" banner
- Add skip navigation link for keyboard users (WCAG 2.4.1)
- Fix heading hierarchy on error page (sr-only status text in h1)
- Add "opens in a new tab" screen reader hint on external links
- Wrap language selector in form with noscript submit button (WCAG 3.2.2)
- Add aria-label to copy-to-clipboard buttons and footer landmarks
- Use h2 for alt-IP section to maintain single h1 per page
- Add persistent underline on links for non-color identification (WCAG 1.4.1)
- Fix footer attribution contrast ratio to ~5.5:1 (WCAG 1.4.3)
- Add aria-busy/role=status loading announcements for skeleton state
- Add translations for new accessibility strings across all 14 locales
- Update integration tests to assert role="alert" instead of alert()
- Add i18n module with Locale enum, PO parser, and Accept-Language negotiation
- Create gettext .po translation files for en, es, de, ja, ko, id, fr, ru, pt, it, zh-Hant, zh-Hans, nl, ar
- Route HTML pages under /{lang}/ prefix using IETF language tags
- Auto-detect browser language and redirect from / to /{lang}/
- Add language selector dropdown in footer
- Localize geo names (country, city) from MMDB where available
- Add hreflang alternate links and multilingual sitemap for SEO
- Support RTL layout for Arabic
- Update integration tests for new routing structure