Continue M4 lib/ de-flattening with domain-agnostic infra:
- lib/hooks/: 9 pure generic hooks (useDebouncedValue, useIsMobile,
useLongPressAction, useRangeSelection, useResizeClientHeight,
useWindowVisibility, useSystemPrefersDark, useVirtualizerScrollMargin,
useRemeasureGridVirtualizer) — all PURE (only react/zustand/tanstack deps).
- lib/dnd/DragDropContext.tsx: the generic mouse-event DnD engine (WebKitGTK
HTML5-DnD workaround, ~24 importers, self-contained) — empties src/contexts/.
- lib/shortcuts/: shortcutActions + shortcutTypes (the action-id + binding
contract; registry/dispatch/bindings stay app-level and import the contract,
app->lib direction).
useWindowFullscreenState deliberately NOT moved — kept in hooks/ as app-shell
per the handoff iron-rule list (overrides its pure-helper appearance).
Pure move via deep @/lib/* specifiers. tsc 0, lint 0/0, full suite 319 files /
2353 tests green.
Psychotoxical