Tapping user avatar or network indicator sends a test signal with
geo data. Backend formats it as "Тест от username" (🧪) instead of
"Сигнал" (🚨). Only active after login on main screen.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Login now requires login/email + password verified against DB via
/api/auth/login. Only approved registrations can access the app.
Signal endpoint accepts JWT Bearer tokens alongside legacy api_key auth.
Old UUID-only registration flow removed from frontend.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>