refactor(core): [CORE-23] complete keyboard controls and focus lifecycle

packages/artplayer/src/accessibility/moved-focus.ts

@@ -0,0 +1,9 @@
+/** Restore the same focused descendant after DOM reparenting. */
+export function captureMovedFocus(root: HTMLElement): () => void {
+  const focused = root.ownerDocument?.activeElement as HTMLElement | null | undefined
+  const inside = focused && root.contains(focused)
+  return () => {
+    if (inside && focused.isConnected && root.contains(focused) && focused.ownerDocument.activeElement === focused.ownerDocument.body)
+      focused.focus({ preventScroll: true })
+  }
+}