Reactive Updates
Type a name and press Save — the breadcrumb updates via optimistic update.
Try changing the name and make a hard reload of the page.
Breadcrumb reads from a remote query
The breadcrumb calls getNickname() — a
server-side query faking a database read.
Optimistic update via command
On save, a command writes to the server
while .withOverride() updates the breadcrumb instantly
— no round-trip.