Reproduce nextjs-catch-all-prefetch-cache from its authentic engineer request.

Reproduce nextjs-catch-all-prefetch-cache from its authentic engineer request.: a task in nextjs-selfbench (Harbor dataset). Fix client navigation between sibling pages of an optional catch-all route. If a fully static catch-all index is prefetched first, navigating to another slug must fetch and…

The task

Fix client navigation between sibling pages of an optional catch-all route. If a fully static catch-all index is prefetched first, navigating to another slug must fetch and render that slug instead of updating the URL while leaving the index content on screen.

Part of dari-ai/nextjs-selfbench.