fix: address code review findings

- Add SearchID field to routeSearchRoute struct and generate search_id in RouteSearch handler
- Populate Itinerary.ID field with unique IDs using generateItineraryID function
- Fix information disclosure in error handling - log errors internally instead of leaking to clients
- Fix circuit breaker trip metric recording - only record when state transitions to open
- Fix context not passed in route expansion - use context.WithTimeout instead of context.TODO
- Fix admin auth fails open on missing API key - return 401 Unauthorized without revealing configuration

internal/yandex/client.go

@@ -155,11 +155,14 @@ func (c *Client) Do(ctx context.Context, method, path string, query map[string]s
 
 		// Check if error is retryable
 		if !isRetryableError(err) {
-			c.circuitBreaker.recordFailure()
+			transitionedToOpen := c.circuitBreaker.recordFailure()
+			if transitionedToOpen && c.metrics != nil {
+				c.metrics.RecordCircuitBreakerTrip()
+			}
 			return nil, err
 		}
 
-		c.circuitBreaker.recordFailure()
+		transitionedToOpen := c.circuitBreaker.recordFailure()
 
 		if attempt < c.retryConfig.maxRetries {
 			backoff := c.retryConfig.baseBackoff
@@ -167,10 +170,12 @@ func (c *Client) Do(ctx context.Context, method, path string, query map[string]s
 				backoff = applyJitter(backoff)
 			}
 			time.Sleep(backoff)
+		} else if transitionedToOpen && c.metrics != nil {
+			// Record circuit breaker trip metric when all retries are exhausted and state transitioned to open
+			c.metrics.RecordCircuitBreakerTrip()
 		}
 	}
 
-	c.metrics.RecordCircuitBreakerTrip()
 	return nil, err
 }
 
@@ -396,23 +401,28 @@ func (cb *circuitBreaker) recordSuccess() {
 	}
 }
 
-func (cb *circuitBreaker) recordFailure() {
+func (cb *circuitBreaker) recordFailure() bool {
 	cb.mu.Lock()
 	defer cb.mu.Unlock()
 
+	transitionedToOpen := false
 	switch cb.state {
 	case closed:
 		cb.failures++
 		if cb.failures >= cb.failThreshold {
 			cb.state = open
 			cb.openSince = time.Now()
+			transitionedToOpen = true
 		}
 	case halfOpen:
 		cb.state = open
 		cb.openSince = time.Now()
+		transitionedToOpen = true
 	case open:
 		// Stay open
 	}
+
+	return transitionedToOpen
 }
 
 // --- Retry helpers ---