feat(toolbar): add column visibility and CSV export features

- Implemented GridToolbar component for column visibility and CSV export
- Added ColumnVisibilityMenu for toggling column visibility
- Created exportToCsv function for exporting visible data to CSV
- Updated Griddy component to integrate toolbar functionality
- Enhanced documentation with examples for new features

src/Griddy/core/Griddy.tsx

@@ -20,6 +20,7 @@ import type { GriddyProps, GriddyRef } from './types'
 import { useKeyboardNavigation } from '../features/keyboard/useKeyboardNavigation'
 import { PaginationControl } from '../features/pagination'
 import { SearchOverlay } from '../features/search/SearchOverlay'
+import { GridToolbar } from '../features/toolbar'
 import { useGridVirtualizer } from '../rendering/hooks/useGridVirtualizer'
 import { TableHeader } from '../rendering/TableHeader'
 import { VirtualBody } from '../rendering/VirtualBody'
@@ -61,6 +62,8 @@ function GriddyInner<T>({ tableRef }: { tableRef: Ref<GriddyRef<T>> }) {
   const height = useGriddyStore((s) => s.height)
   const keyboardNavigation = useGriddyStore((s) => s.keyboardNavigation)
   const className = useGriddyStore((s) => s.className)
+  const showToolbar = useGriddyStore((s) => s.showToolbar)
+  const exportFilename = useGriddyStore((s) => s.exportFilename)
   const manualSorting = useGriddyStore((s) => s.manualSorting)
   const manualFiltering = useGriddyStore((s) => s.manualFiltering)
   const dataCount = useGriddyStore((s) => s.dataCount)
@@ -253,6 +256,12 @@ function GriddyInner<T>({ tableRef }: { tableRef: Ref<GriddyRef<T>> }) {
       role="grid"
     >
       {search?.enabled && <SearchOverlay />}
+      {showToolbar && (
+        <GridToolbar
+          exportFilename={exportFilename}
+          table={table}
+        />
+      )}
       <div
         className={styles[CSS.container]}
         ref={scrollRef}