Assignments admin — the overview of every template binding + a single modal for creating or editing an assignment.
Layout:
- Top: header + "Assign template" button.
- Overview list: every assignment (module-default row, per-group rows) with the template it points at + row actions (edit, remove).
- Assignment modal: opened for both "new" and "edit". Carries
scope, group (when scope=group), template, and the per-slot
wiring dropdowns — all in one place. Local
@edit_stateholds the in-progress config until the user hits Save.