pota/use/selector

pota/use/selector provides small reactive helpers: useSelector builds derived selection state from a source signal using a single shared effect (not one per value), so it scales to long lists; and usePrevious gives a function access to its own previous return value.

Exports

• useSelector(source) — isSelected factory without O(n) updates
• usePrevious(fn) — wrap fn so it receives its previous return value