Refactor admin to shared generic CRUD; restructure proclamation categories/groups and APIs

- Replace per-model admin forms with the shared generic AdminTable/AdminModal CRUD
- Add ProclamationGroup model and admin + API v2 routes (replaces subscription levels)
- Drop subscription levels and flatten proclamation categories
- Update v2 serializers and seed data accordingly

src/lib/svelte-admin/crud.spec.ts

@@ -20,8 +20,8 @@ vi.mock('$lib/db', () => {
 			userRole: mkdel(),
 			proclamation: mkdel(),
 			proclamationCategory: mkdel(),
-			solfeggioFrequency: mkdel(),
-			subscriptionLevel: mkdel()
+			proclamationGroup: mkdel(),
+			solfeggioFrequency: mkdel()
 		}
 	};
 });