account export was CLI-only. GET /settings/export dispatches the same
read-only command as the session user and serves its stdout as an attachment
named <username>.bundle. A GET is enough because the command is ReadOnly.
The settings page's "On SSH only" block listed gitbay auth export > account.bundle, which is not a command — the export section replaces that line.
Covered in TestAccountSettingsWeb: the attachment header, and the bundle
parsing as the same JSON the CLI writes. Parity row updated.
Two neighbouring rows in the matrix are stale and not touched here: build cancel and profile set both have web UI already.
Closes #166