feat: thread and persist sub_pattern into accepted questions

tools/generate_questions.py

@@ -323,6 +323,23 @@ def _build_embed_provider():
 # ---------------------------------------------------------------------------
 
 
+def _question_to_entry(question: GeneratedQuestion) -> dict:
+    """将题目序列化为 JSON entry（_append_to_json 与 _on_accept 共用）。"""
+    return {
+        "question_id": question.question_id,
+        "video_id": question.video_id,
+        "task_type": question.task_type,
+        "question": question.question,
+        "options": list(question.options),
+        "answer": question.answer,
+        "source_nodes": list(question.source_nodes),
+        "difficulty": question.difficulty,
+        "family": question.family,
+        "skill_target": question.skill_target,
+        "sub_pattern": question.sub_pattern,
+    }
+
+
 def _append_to_json(output_dir: Path, question: GeneratedQuestion) -> None:
     """将生成的题目追加到对应 video_id 的 JSON 文件。
 
@@ -341,17 +358,7 @@ def _append_to_json(output_dir: Path, question: GeneratedQuestion) -> None:
             logger.warning("读取 {} 失败，覆盖写入", json_path)
             existing = []
 
-    entry = {
-        "question_id": question.question_id,
-        "task_type": question.task_type,
-        "question": question.question,
-        "options": list(question.options),
-        "answer": question.answer,
-        "source_nodes": list(question.source_nodes),
-        "difficulty": question.difficulty,
-        "family": question.family,
-        "skill_target": question.skill_target,
-    }
+    entry = _question_to_entry(question)
     existing.append(entry)
 
     # 原子写入
@@ -1120,20 +1127,7 @@ async def _run_generate_v2(args: argparse.Namespace) -> None:
             except (json.JSONDecodeError, OSError):
                 existing = []
 
-        existing.append(
-            {
-                "question_id": q.question_id,
-                "video_id": q.video_id,
-                "task_type": q.task_type,
-                "question": q.question,
-                "options": list(q.options),
-                "answer": q.answer,
-                "source_nodes": list(q.source_nodes),
-                "difficulty": q.difficulty,
-                "family": q.family,
-                "skill_target": q.skill_target,
-            }
-        )
+        existing.append(_question_to_entry(q))
 
         tmp_path = output_path.with_suffix(".tmp")
         tmp_path.write_text(