discard adjustable models' id prefix & payload length

app/models/library.py

@@ -1,18 +1,13 @@
-from typing import TYPE_CHECKING
 from sqlalchemy import Column, DateTime, String, ForeignKey, BigInteger
 from sqlalchemy.sql import func
 from .base import AutoID, Base
 
-if TYPE_CHECKING:
-    from .user import User
-    from .workspace import Workspace
-
 class LibraryItem(Base, AutoID):
     """工作区共享媒体/文件资源库"""
     __tablename__ = "library_items"
 
     workspace_id = Column(
-        String(Workspace.id_length()),
+        String(AutoID.id_length()),
         ForeignKey("workspaces.id", ondelete="CASCADE"),
         index=True,
     )
@@ -34,7 +29,7 @@ class LibraryItem(Base, AutoID):
     mime_type = Column(String, nullable=True)      # 媒体类型，例如 'image/jpeg', 'video/mp4', 'application/pdf'
     
     uploaded_by = Column(
-        String(User.id_length()),
+        String(AutoID.id_length()),
         ForeignKey("users.id", ondelete="SET NULL"),
         nullable=True,
     )