Move `RepeatMode` display to their own file

`displayName`, `systemImageName_menuItem`, and `systemImageName_preview` are defined at the bottom of a UI file rather than beside the type or in a dedicated extension file, which is the pattern everywhere else in the project.

Locate the UI file containing displayName, systemImageName_menuItem, and systemImageName_preview, then inspect nearby types and dedicated extension files to follow the project’s existing organization pattern. Move the RepeatMode display members into their own file or beside the type as appropriate, and verify that the project still builds and the display values remain available.

Written by the indexing model from the issue text.