Mark quiz-lead merge logic with decision D-BIZ-017

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/lib/quiz-lead.ts

@@ -185,6 +185,7 @@ export type ExistingPlan =
       };
     };
 
+// РЕШЕНИЕ D-BIZ-017: список — через subscribers/lists add, атрибуты — PUT с текущими списками без preconfirm
 export function planExisting(sub: ListmonkSubscriber, lead: QuizLead, listId: number, now: Date): ExistingPlan {
   if (sub.status === "blocklisted") return { kind: "skip", reason: "blocklisted" };
   const current = sub.lists.map((l) => l.id);