perf(explorer): client side explorer (#1810)

* start work on client side explorer

* fix tests

* fmt

* generic test flag

* add prenav hook

* add highlight class

* make flex more consistent, remove transition

* open folders that are prefixes of current path

* make mobile look nice

* more style fixes

quartz.config.ts

@@ -8,7 +8,7 @@ import * as Plugin from "./quartz/plugins"
  */
 const config: QuartzConfig = {
   configuration: {
-    pageTitle: "🪴 Quartz 4",
+    pageTitle: "Quartz 4",
     pageTitleSuffix: "",
     enableSPA: true,
     enablePopovers: true,