createW3CTreeStrategy

Description#

Default W3C APG treeview keyboard policy:

• ArrowRight on a collapsed parent expands it. On an already-open parent it moves the active-descendant to the first child. On a leaf it is a no-op.
• ArrowLeft on an open node collapses it. On a closed node (or leaf) with a parent it moves the active-descendant to the parent. On a root leaf it is a no-op.

Move actions internally verify that ad.highlightByValue actually changed activeId (e.g. disabled skip rejection), and downgrade to 'noop' when it didn't - so consumers bound to (movedToChild) / (movedToParent) only see state-change-truthful emissions.

onArrowRight / onArrowLeft are the inline-forward / inline-back intents, not physical keys. CngxHierarchicalNav resolves the physical arrow to its logical intent by writing direction (resolveInlineArrowKey) before calling the strategy, so under rtl physical ArrowLeft routes to onArrowRight. Custom strategies stay direction-naive and inherit correct RTL behaviour for free.