bf4b6dad2d
New tab copies the source tab's video list + separators, gets a unique
"<name> copy" label and an adapted own export folder ("<folder>_copy"), and
inherits the tab-named-folder flag. No files are moved or copied — you export
into the new tab's folder. Keeps Foley/variant datasets separate without the
file-shuffling that a misexport used to require.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>