What this flow does

The upload card on Email Newsletters -> Distribution Lists is the real operational entrypoint for creating or extending recipient lists.

The flow is:

1. choose an optional target list
2. select a CSV file
3. preview the file
4. upload the file
5. create a list automatically when no target list is selected
6. parse emails from the CSV before attaching contacts
7. attach the parsed emails to the chosen or newly created list
8. show the final result modal

The same card also contains a paged distribution-list table. Its ID, Name, Size, and Actions columns are there to help the operator inspect or rename existing lists before choosing a target for upload.

Important caveats

• The target-list selector uses an empty value labelled Create new list. That is not a placeholder-only state; it is the actual create branch.
• Check File and Upload CSV are different steps. Preview validates the file first; upload performs the persistent flow.
• Preview does not clear the selected file. The page keeps the file selected until a successful upload resets the input.
• The parser looks for an email or emailAddress column. If the file has only one column, that single column is treated as the email column.
• Upload CSV can run even when Check File was never used.
• The create-list branch happens only after a successful file upload.
• The default new-list name comes from the uploaded file name, with a timestamp fallback only when the file base name is empty.
• Attach errors can appear even when the file upload itself succeeded.
• The final dialog title is File Result and is reused for both preview and upload outcomes.
• The table's top and bottom pagination controls refetch the list query. Large page-size options are available, but they can make the downstream newsletter request slower.