A tiny "remember-me" flow. On the first visit you'll see a
form asking for your name. Submitting it writes
session.greetName, which triggers lazy-init: the
engine inserts the session record into KV, fires
onSessionStart, and sends back a Set-Cookie
header. From then on, every visit hydrates the session from KV
and greets you back.
If you never submit the form, nothing is persisted, no cookie is issued, and the next request is just as cheap as the first.
No greetName in session yet — looks like this
is your first visit (or you cleared the cookie). Enter a name
and we'll remember you.