Faster asset grid, and key media library bugfixes

This release makes the asset grid dramatically faster in large libraries, plus fixes for the "In use" dialog and array aspects in the edit form.

The asset grid now renders only the assets in the viewport, plus a small buffer. Previously every loaded asset stayed in the page as you scrolled, so libraries with more than a few thousand assets became progressively slower. Scrolling, selection, and loading behave exactly as before — there's just far less work happening behind the scenes.

• The "In use" dialog no longer shows a React error for every referencing document when a document's title is stored as an internationalized array. Localized titles now display their actual value rather than falling back to a generic label
• The "In use" dialog no longer hangs on skeleton loaders forever when opened from the Media Library plugin inside Studio. Referencing documents now load and display, showing the document title, type, and perspective
• Array-of-objects aspects with more than around ten items no longer render blank or misplaced rows in the edit sidebar. Scrolling now updates the list correctly, and items added through the "Add item" dialog appear where you expect them, both in the sidebar and in the plugin's edit dialog