feat: subpages component improvements - #2488

Improves subpage sorting and recursive nested-page rendering.

Changes:

• Adds persisted sort options and editor controls.
• Supports expandable, lazy-loaded nested subpages.
• Adds sorting utilities and nested-row styling.

Suppressed comments (4)

apps/client/src/features/editor/components/subpages/subpage-item.tsx:62

• This is an infinite query with a cursor and a 100-item limit, but the nested renderer only flattens pages already fetched and never calls fetchNextPage or exposes hasNextPage. A parent with more than 100 children will silently omit the remainder, so load all pages or provide a load-more path.

    const pages = data?.pages.flatMap((result) => result.items) || [];
    return sortSubpages(pages, sortBy);

apps/client/src/features/editor/components/subpages/subpages-view.tsx:23

• sortSubpages only treats "default" as the position-order sentinel; any other value falls into the title-ascending branch. Using "position" here therefore changes nodes with a missing sortBy attribute to alphabetical order instead of preserving the existing position order. Use "default" as the fallback.

  const sortBy = (props.node.attrs.sortBy || "position") as SubpagesSortBy;

apps/client/src/features/editor/components/subpages/subpages.utils.ts:3

• This union duplicates the SubpagesSortBy type exported by @docmost/editor-ext (and now used by the node command). Keeping separate declarations can let the renderer and editor command accept different values; import and re-export the package type here so the existing local imports share one source of truth.

export type SubpagesSortBy = "default" | "title-asc" | "title-desc";

apps/client/src/features/editor/components/subpages/subpages.utils.ts:22

• sortBy is typed as a union, but runtime values are not guaranteed: the view currently falls back to "position", and the node parser accepts arbitrary data-sort-by strings. Such a value skips this default check and is treated as ascending title order below, so malformed or legacy nodes can lose their position ordering. Normalize unsupported values to the default/position branch here.

  if (sortBy === "default") {
    return sortPositionKeys(sortedItems);
  }

• Files reviewed: 7/7 changed files
• Comments generated: 5
• Review effort level: Lite