Replace manual BackButton management with official @telegram-apps/react-router-integration
to fix navigation issues (back button cycling and double-click).
Changes:
- Migrate from @tma.js/sdk-react to @telegram-apps/sdk-react
- Downgrade react-router-dom to v6 for package compatibility
- Add AppWithNavigator component with Telegram navigator integration
- Use browser history mode (hashMode: null) to prevent hash URLs
- Add multi-level platform detection (user data, platform, version)
- Add try-catch error handling for navigator attach/detach
- Simplify useBackButton hook to no-op (navigator handles automatically)
- Update vite config with new Telegram packages
The navigator automatically manages BackButton based on router history,
falling back to BrowserRouter in regular browser environment.
Major changes:
- Redesign cabinet with Linear-style components and top navigation
- Replace detail modals with dedicated pages (users, broadcasts, email templates)
- Add email channel support for broadcasts
- Remove pull-to-refresh, improve drag-and-drop on touch devices
- Fix Telegram Mini App: fullscreen, back button, scroll restoration
- Unify admin pages color scheme to design system
- Mobile-first improvements: horizontal tabs for settings, better touch targets
