fix: address code review findings

internal/yandex/client.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"math/rand"
 	"net/http"
 	"net/url"
@@ -189,9 +190,10 @@ func (c *Client) executeRequest(ctx context.Context, url string) (*Response, err
 	if err != nil {
 		return nil, fmt.Errorf("request failed: %w", err)
 	}
-	defer resp.Body.Close()
 
 	if resp.StatusCode >= 400 {
+		io.ReadAll(resp.Body) // Drain body to allow connection reuse
+		resp.Body.Close()
 		return nil, newAPIError(resp.StatusCode, resp.Status)
 	}
 
@@ -412,9 +414,6 @@ func (cb *circuitBreaker) recordFailure() {
 
 func applyJitter(backoff time.Duration) time.Duration {
 	jitter := time.Duration(float64(backoff) * 0.1 * (randFloat64()*2 - 1))
-	if jitter < 0 {
-		jitter = -jitter
-	}
 	return backoff + jitter
 }