Problem:
The topRepo column in the DevIndex grid maps to an array ['repoName', count]. Default sorting fails because it compares array references rather than the contribution count.

Proposed Solution:
Leverage "Turbo Mode" soft hydration by adding a topRepoCount virtual field to DevIndex.model.Contributor and intercepting the sort property inside DevIndex.view.home.GridContainer#onSortColumn to sort by this count.

• apps/devindex/model/Contributor.mjs: Add topRepoCount virtual field using (data.topRepo ?? data.tr)?.[1] || 0.
• apps/devindex/view/home/GridContainer.mjs: Override onSortColumn to swap topRepo for topRepoCount in sortOpts before passing to the store, preserving the original property for removeSortingCss to keep visual state correct.