Central file storage and management. Files are uploaded via a resumable chunked upload protocol and can be attached to any supported entity (Contact, Todo, Business Case, Product, etc.).

Upload flow: Use POST /{module}/{id}/file with multipart/form-data and the resumable chunk parameters (resumableChunkNumber, resumableIdentifier, resumableTotalChunks, etc.). Poll upload progress with GET /{module}/{id}/file?resumableIdentifier={id}.

Download: GET /file/{fileId}/download streams the file. MIME type and file size are validated on upload. Storage path is sanitised to prevent directory traversal.

Permissions: File access follows the permissions of the parent entity it is attached to.