- Validate authorize_url is HTTPS before redirect (open redirect prevention)
- encodeURIComponent on provider name in API URL paths (path traversal prevention)
- encodeURIComponent on referralCode in t.me deep link
- Gate console.warn behind import.meta.env.DEV (no info leak in prod)
- Add OAuthProvider type and extend User.auth_type union
- Add OAuth API methods (providers, authorize, callback)
- Add loginWithOAuth to auth store
- Create OAuthCallback page with state validation
- Create OAuthProviderIcon component with brand SVGs
- Add OAuth buttons to Login page between Telegram and Email
- Add OAuth callback route to App.tsx
- Add translations for ru, en, zh, fa