FIX: Handle NULL transports in credentials using pq.StringArray

go_cloud/internal/database/db.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/google/uuid"
+	"github.com/lib/pq"
 )
 
 type DB struct {
@@ -35,7 +36,7 @@ type Credential struct {
 	SignCount           int64
 	CreatedAt           time.Time
 	LastUsedAt          *time.Time
-	Transports          []string
+	Transports          pq.StringArray
 }
 
 type AuthChallenge struct {