refactor(aria/grid): Add accessors for pattern properties

Author: adolgachev

src/aria/grid/grid.ts

@@ -86,6 +86,12 @@ export class Grid {
   /** Whether enable range selections (with modifier keys or dragging). */
   readonly enableRangeSelection = input(false, {transform: booleanAttribute});
 
+  /** Whether the user is currently dragging to select a range of cells. */
+  readonly dragging = computed(() => this._pattern.dragging());
+
+  /** Whether the focus is in the grid. */
+  readonly isFocused = computed(() => this._pattern.isFocused());
+
   /** The UI pattern for the grid. */
   readonly _pattern = new GridPattern({
     ...this,