Implements i18next translation and theme context on SettingsPage.tsx. Replit-Commit-Author: Agent Replit-Commit-Session-Id: ff0be73b-afdd-4747-978b-bb8301fb0a82 Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/9777c70b-fc38-4831-8d6b-78dfffe041b0/dd3530ea-4bd5-42ed-a7b3-376f722f9e6d.jpg