New techniques for storing state in querystring

demo/index.html

@@ -27,6 +27,7 @@
       const tree = new CheckboxTree(document.querySelector("#tree"), {
         initiallySelected: true,
         manifest,
+        stateEncoding: "tiered",
         onSelectionChange({ selectedIds }) {
           output.textContent = JSON.stringify(selectedIds, null, 2);
         },