feat: implement Yandex API client with rate limiter and circuit breaker

docs/plans/2026-08-13-MVP-Routing-Implementation.md

@@ -63,14 +63,14 @@ Implement the Minimum Viable Product for the multimodal trip planning service, f
 - [x] Run initial tests - must pass
 
 ### Task 2: Implement Yandex API client with rate limiter and circuit breaker
-- [ ] Create `internal/yandex/client.go` with Yandex API wrapper
-- [ ] Implement token bucket rate limiter (configurable TPS limit)
-- [ ] Implement circuit breaker pattern (states: closed, open, half-open)
-- [ ] Add retry with exponential backoff for transient errors
-- [ ] Write tests for rate limiter (token consumption, refill rate)
-- [ ] Write tests for circuit breaker (state transitions, trip to open state)
-- [ ] Write tests for retry (success after backoff, exhaustion)
-- [ ] Run tests - must pass before task 3
+- [x] Create `internal/yandex/client.go` with Yandex API wrapper
+- [x] Implement token bucket rate limiter (configurable TPS limit)
+- [x] Implement circuit breaker pattern (states: closed, open, half-open)
+- [x] Add retry with exponential backoff for transient errors
+- [x] Write tests for rate limiter (token consumption, refill rate)
+- [x] Write tests for circuit breaker (state transitions, trip to open state)
+- [x] Write tests for retry (success after backoff, exhaustion)
+- [x] Run tests - must pass before task 3
 
 ### Task 3: Implement cache-aside layer for reference data and search results
 - [ ] Create `internal/cache/store.go` with Redis cache interface