HasNoLinkedRepo on ListsIslandViewModel drives a dismiss-less banner under the
Lists-Island header when no User list has a linked repo; recomputed on load
and after list CRUD / list-settings save. Sharpens the #192 empty-state texts
into one readable chain (banner → no-repo list → repo-linked list) and adds a
line to the WorkConsole review gate spelling out that Approve also merges the
whole unit.
