Add web push notifications for new inbox items

web/src/app.ts

@@ -59,6 +59,13 @@ async function main(): Promise<void> {
 
   addEventListener("hashchange", route);
   route();
+
+  if ("serviceWorker" in navigator) {
+    navigator.serviceWorker.onmessage = (e: MessageEvent<{ open: string }>) => {
+      location.hash = new URL(e.data.open, location.origin).hash;
+    };
+    await navigator.serviceWorker.register("/sw.js");
+  }
 }
 
 main().catch((err: unknown) => {