- Make MBOX/PST upload size limits configurable via SETTINGS
(bichon_web_mbox_upload_limit_mb defaults to 1 GB,
bichon_web_pst_upload_limit_mb defaults to 2 GB)
- Treat MIME parts with Content-ID but no Content-Disposition as inline
- Add account_ids filter to CLI export search to avoid pulling all accounts
- Skip failed emails during export instead of aborting the entire batch