Multi-language UI (TR / EN)

[Metrohan]

Summary

Internationalize the frontend so non-Turkish users can navigate and use the platform in English.

Why

As the project grows toward global coverage, the UI must be accessible to non-Turkish speakers. This is a prerequisite for Phase 4.

Acceptance criteria

• i18n library integrated (e.g. react-i18next)
• All static UI strings externalized to translation files
• Language switcher in the header (TR / EN)
• Language preference persisted in localStorage

Phase

Roadmap Phase 4 — Internationalization