feat(navigation): add support for custom routes with route tokens

[david-pivonka]

Summary

Implements integration with Google Routes API by adding setRouteToken method to NavigationController. This addresses issue #398 by allowing developers to use pre-calculated routes from the Routes API in the Navigation SDK.

Changes Made

• ✅ TypeScript Interface: Added setRouteToken method to NavigationController interface
• ✅ Android Implementation: Added native setRouteToken method using setDestinationsWithRouteToken
• ✅ iOS Implementation: Added native setRouteToken method using setDestinationsWithRouteToken
• ✅ React Native Bridge: Integrated TypeScript and native implementations
• ✅ Documentation: Added usage examples and API documentation to README
• ✅ Example App: Added demonstration button in sample app navigation controls

API Addition

setRouteToken(
  routeToken: string,
  displayOptions?: DisplayOptions
): Promise<void>;

Usage Example

try {
  // First, obtain a route token from the Google Routes API
  const routeToken = "your_route_token_from_routes_api";
  
  const displayOptions = {
    showDestinationMarkers: true,
    showStopSigns: true,
    showTrafficLights: true,
  };

  await navigationController.setRouteToken(routeToken, displayOptions);
  await navigationController.startGuidance();
} catch (error) {
  console.error('Error starting navigation with route token', error);
}

Test plan

• TypeScript compilation passes
• Linting passes
• Build succeeds for all targets (commonjs, module, typescript)
• Cross-platform implementation (Android + iOS)
• Added example usage in sample app
• Integration tests (to be added if requested)
• Manual testing with actual route tokens from Routes API

Notes

The implementation follows the same patterns as existing setDestinations methods and integrates seamlessly with the current Navigation SDK architecture. Route tokens must be generated using the Google Routes API as documented.

Fixes #398

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