Document Management

class Document(CremeEntity):
    """
    Document entity for file management and organization.

    Attributes:
    - title: str, document title
    - description: TextField, document description
    - filedata: FileField, uploaded file
    - mime_type: str, MIME type of file
    - linked_folder: ForeignKey, parent folder

    Methods:
    - get_download_url(): Get file download URL
    - get_file_size(): Get file size in bytes
    """

class Folder(CremeEntity):
    """
    Folder entity for document organization.

    Attributes:
    - title: str, folder name
    - description: TextField, folder description
    - parent_folder: ForeignKey, parent folder for hierarchy

    Methods:
    - get_documents(): Get documents in folder
    - get_subfolders(): Get child folders
    """