Fold the skill hub (search/preview/scan/install, from #57441) into Capabilities
as a fourth "Browse Hub" tab, rebuilt on our stack:
- sources + debounced term search + preview are useQuery-driven (RQ dedupes/
caches per term, cancels stale terms — no hand-rolled sequence guard).
- Each result is a self-contained HubSkillRow that installs/uninstalls ITSELF,
reading its own status from a nanostore (store/hub-actions). Concurrent
installs never desync; an optimistic installed-override flips a row the instant
its own action resolves instead of racing the sources refetch.
- Action log bubbles through a $hubActiveLog atom into the shared LogTail in a
collapsed-by-default, persistent bottom DetailPane (ANSI stripped).
929ba007bb