Migrate to Telegram Navigator integration

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.

vite.config.ts

@@ -49,7 +49,11 @@ export default defineConfig({
             '@radix-ui/react-visually-hidden',
           ],
           'vendor-dnd': ['@dnd-kit/core', '@dnd-kit/sortable', '@dnd-kit/utilities'],
-          'vendor-telegram': ['@tma.js/sdk-react'],
+          'vendor-telegram': [
+            '@telegram-apps/sdk',
+            '@telegram-apps/sdk-react',
+            '@telegram-apps/react-router-integration',
+          ],
           'vendor-utils': [
             'axios',
             'zustand',