feat: 游玩记录支持区分原故事和AI草稿，已下架草稿显示标签

server/app/models/user.py

@@ -65,6 +65,7 @@ class PlayRecord(Base):
     id = Column(Integer, primary_key=True, autoincrement=True)
     user_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False)
     story_id = Column(Integer, ForeignKey("stories.id", ondelete="CASCADE"), nullable=False)
+    draft_id = Column(Integer, default=None)  # AI草稿ID，原故事为空
     ending_name = Column(String(100), nullable=False)  # 结局名称
     ending_type = Column(String(20), default="")  # 结局类型 (good/bad/hidden/rewrite)
     path_history = Column(JSON, nullable=False)  # 完整的选择路径