refactor(auth): migrate to zerolog structured logging

internal/auth/login.go

@@ -10,7 +10,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"log"
 	"net"
 	"net/http"
 	"net/url"
@@ -20,6 +19,8 @@ import (
 	"runtime"
 	"strings"
 	"time"
+
+	"github.com/rs/zerolog/log"
 )
 
 const (
@@ -246,7 +247,7 @@ func exchangeAuthCode(ctx context.Context, code, state, verifier string, port in
 		return nil, fmt.Errorf("save credential: %w", err)
 	}
 
-	log.Printf("login successful, credentials saved to %s", credPath)
+	log.Info().Str("path", credPath).Msg("login successful, credentials saved")
 	return cred, nil
 }