test(ci): add exporter heading levels and a11y typography smoke; update MAIN_PLAN

lib/utils/reorder.ts

@@ -0,0 +1,15 @@
+export function move<T>(arr: T[], from: number, to: number): T[] {
+  if (
+    from === to ||
+    from < 0 ||
+    to < 0 ||
+    from >= arr.length ||
+    to >= arr.length
+  ) {
+    return arr
+  }
+  const next = arr.slice()
+  const [sp] = next.splice(from, 1)
+  next.splice(to, 0, sp)
+  return next
+}