feat: add useContextMenu consumer hook

packages/web/src/hooks/useContextMenu.ts

@@ -0,0 +1,26 @@
+// packages/web/src/hooks/useContextMenu.ts
+import { useCallback, useRef } from 'react';
+import { useContextMenuStore, type ContextMenuItem } from '../stores/contextMenuStore';
+
+/**
+ * Returns an onContextMenu handler that opens the centralized context menu.
+ *
+ * Items are captured via a ref so the callback identity is stable regardless
+ * of whether the caller memoises the array. The ref is updated every render,
+ * so items are always fresh at event-fire time.
+ */
+export function useContextMenu(items: ContextMenuItem[]) {
+  const itemsRef = useRef(items);
+  itemsRef.current = items;
+
+  const onContextMenu = useCallback((e: React.MouseEvent) => {
+    e.preventDefault();
+    e.stopPropagation();
+    useContextMenuStore.getState().open(
+      { x: e.clientX, y: e.clientY },
+      itemsRef.current,
+    );
+  }, []);
+
+  return { onContextMenu };
+}