Security — Files & attachments

Uploaded files are never written to a publicly served directory. They go to blob storage (or, in local development, to a directory outside the web root), and the only way to read one back is through an endpoint that checks your permission on the owning record first. A file's URL is not a capability: knowing it does not grant access to it. Attachment metadata is also excluded from every text-based write path in the product — imports, the API, AI edits, and grid pastes cannot construct or alter it. That closes the route by which a crafted value could otherwise be made to point at another account's stored file.