- Remove Population field from HubStation; hub selection now uses only outgoing flights criterion
- Simplify SelectHubStations criteria (minPopulation removed from function calls)
- Add synthetic edge fallback in FindRoute when lazy expansion fails
- Add ResetCircuitBreaker helper to yandex client for test reset
- Update test criteria to match new hub selection logic
- Remove TestLazySearchCacheIntegration (replaced by integration tests)
- Add SearchRoutes method to yandex client for on-demand station pair searches
- Implement hub expansion via on-demand /search calls in lazy graph expansion
- Integrate cache key generation for search results (search:{from}:{to}:{date})
- Update expandFromStation and expandFromCityHub to use Yandex API
- Add NewGraphWithoutYandex constructor for testability
- Add tests for on-demand search integration and cache TTL policies