refactor: repartition server-side and client-side code

app/types/pages.ts

@@ -0,0 +1,9 @@
+import type { Page, Section } from '~/types/actions';
+
+export type PageSection = Section & {
+  validRootDomId?: boolean;
+};
+
+export type PageMap = Record<string, Page | undefined>;
+
+export type SectionMap = Record<string, PageSection | undefined>;