rename project node -> project item

app/models/project.py

@@ -2,13 +2,13 @@ from sqlalchemy import Column, DateTime, String, ForeignKey, Integer
 from sqlalchemy.sql import func
 from .base import AutoID, Base
 
-class ProjectNode(Base, AutoID):
+class ProjectItem(Base, AutoID):
     """项目与文件夹的树状虚拟文件系统"""
-    __tablename__ = "project_nodes"
+    __tablename__ = "project_items"
 
     workspace_id = Column(String(32), ForeignKey("workspaces.id", ondelete="CASCADE"), index=True)
     # 自引用外键：如果是根目录下的顶级节点，则 parent_id 为 Null
-    parent_id = Column(String(32), ForeignKey("project_nodes.id", ondelete="CASCADE"), nullable=True, index=True)
+    parent_id = Column(String(32), ForeignKey("project_items.id", ondelete="CASCADE"), nullable=True, index=True)
     
     name = Column(String, nullable=False)
     # 节点类型：'folder' (文件夹) 或 'project' (代表具体文件的项目实体)