- Add metrics package tracking cache hit-rate, API quota, circuit breaker trips, search time
- Integrate metrics with cache layer, yandex client, and API handlers
- Add /metrics HTTP endpoint for Prometheus-compatible metrics exposure
- Write tests for metrics functionality across cache, yandex, and API handlers
- Update test files to support new metrics infrastructure
- Create cmd/api/handlers.go with HTTP handlers for all MVP endpoints
- Implement GET /v1/cities?query= city autocomplete
- Implement GET /v1/cities/{id}/stations city stations including neighbors
- Implement POST /v1/routes/search route search with Pareto-optimal results
- Implement GET /v1/routes/{search_id}/{route_id}/geojson route geometry
- Implement GET /v1/stations/{id}/status station status endpoint
- Add handler tests with success and error cases
- All existing tests pass
