Run: `detail-shell-back-link-viewer`

`run.md`

change: apps/demo/components/dashboard/detail-page-shell.tsx: back-link href /dashboards/<persona> → hrefAs("/dashboards/<persona>", viewer.id), so returning from any of the 22 detail stubs keeps you signed in as the same person instead of resetting to the dashboard's default (last unfixed instance of the #777 viewer-reset bug).
note: the ?as= stamp needs useViewer(), but 14 of the 22 pages are Server Components that pass icon as a component type — which cannot cross the server→client boundary. So the wrapper stays a Server Component and the hook moved into a new client half, detail-page-shell-frame.tsx. No call site changed.
changelog: not warranted — demo-only routing fix, matches the behaviour sidebar.tsx and leads-view.tsx already have.