feat(site): Send the daily reminder by browser notification

[WillieCubed]

TL;DR

Participants can turn on one browser notification each morning of Week Without Driving, October 1 to
8, from My week, and stop it with one tap. Each notification asks them to leave the car at home and
share that day's trip, and tapping it opens My week. The Worker sends them itself, encrypted and
signed with Web Crypto, with no new dependency, and the production guide says exactly what a
maintainer needs to run to turn it on.

Overview of Changes

The reminder message list

Each morning, a participant who turns on reminders gets one short message asking them to leave the
car at home and share that day's trip on My week, with one idea to try. The eight messages live in
one place, apps/site/src/data/reminders.json, word for word as the campaign wrote them: each day's
notification title and body, and the text message a future text channel will send, with {link}
where the person's own "Open my week" link goes. Every build and every pnpm dev checks the list and
stops with the message's date and the broken rule when an edit breaks one — eight messages in date
order, titles and texts that name their day, the mail-in line on days 1 and 8, and texts that fit in
one standard text message with the 45-character link, in plain characters only.

Turning reminders on and off

My week's "Remind me to share my trip" section opens with its heading and a line saying what the
reminder is, then "Browser notifications." Tapping "Turn on notifications" answers the browser's own
question, subscribes with the Worker's public key and saves the subscription for the signed-in
person; "Stop reminders" cancels the subscription in the browser first, so it works offline, then
deletes the record. An iPhone outside the Home Screen gets the existing "Add to your Home Screen"
steps; a browser that can't show notifications gets a plain line instead of a button. From 8:00 am on
October 8 the section shows only its closing line. Signing out leaves a phone's reminders on, as
designed. The old yes-or-no choices for notifications, texts and email never sent anything and
nobody had saved one, so their table and route are gone.

How the morning send works

Subscriptions live in the new push_subscriptions table. A Cron Trigger fires on the odd minutes
from 8:01 to 8:59 am Las Vegas time, October 1 to 8, and each run sends that date's message to the
next 40 browsers that turned reminders on before 8:00 am, six at a time, encrypted for each. A
browser gets a day's message once; one its push service reports gone is deleted, and anything else is
tried again on the next run. The Worker's scheduled handler now picks the job by its Cron Trigger, so
the daily cleanup and the reminders never run each other's work, and a text channel can be added
later beside browser notifications on the even minutes. Volunteers get a "Send test reminder" button
in /admin, and the API preview sends its pinned day's reminder to each new browser every five
minutes.

Encryption and keys

Each notification is encrypted for its browser alone (RFC 8291, aes128gcm) and signed with a 12-hour
VAPID token for its push service (RFC 8292, ES256), both written with Web Crypto alone in
apps/site/worker/push/, so nothing new is added to run on Workers. platform.json declares one new
secret, VAPID_PRIVATE_KEY, generated once by pnpm bootstrap --production; the Worker works the
public key out from the private key and serves it at GET /api/push/key, so the two can never
disagree. The tests reproduce RFC 8291's worked example byte for byte, derive the RFC's sender public
key from its private key, read messages back with a stand-in browser's key, and verify the token's
signature.

What production needs

A maintainer runs pnpm bootstrap --production once after this merges; it applies migration 0006
and generates VAPID_PRIVATE_KEY without anything to type or copy. The production guide now lists
what reminders need and where each value lives: VAPID_PRIVATE_KEY (generated once, never replaced
on a later run), the public key the Worker derives from it, VAPID_SUBJECT and the send times
already in wrangler.jsonc, and the subscriptions table the same command's migrations add. It says
the owner does nothing by hand, how to replace a leaked key on purpose, and how to test a phone
before October 1 with "Send test reminder." The Privacy page says what turning on reminders keeps,
who delivers them, and that the record is deleted when you stop or on November 30, 2026.

lvwwd.org/keep-going

Day 8's reminder points to "Keep going after the week" on My week. /keep-going reaches it from
anywhere: on a phone signed in to My week, a small script opens My week at the card; on any other
phone it opens LVBT's join page. Both replace the page, so Back doesn't bounce into the redirect
again. Without JavaScript, the page shows the card's heading and line with both links, and it asks
search engines not to index it.

How it was tested

Vitest against a local D1 covers the RFC 8291 vector and VAPID tokens; subscribing and the 401, 400
and 410 replies; the schedule (40 a run then the rest, the 8:00 am cutoff, nothing outside the week
or on another Cron Trigger); gone and failing push services; sign-out leaving reminders on; and
deletion on November 30. The service worker tests show and tap each of the eight reminders. Playwright
covers the section's states, turning on and off, /keep-going signed in and out and with JavaScript
off. On the API preview, Chrome signed up, turned reminders on, and received the pinned day's message
a few minutes later through Google's push service. pnpm check passes.

Follow-ups

• Send the daily reminder by text message once LVBT's Twilio registration is approved.
• Record the reminder_opt_in analytics event once LVBT's analytics allow lvwwd.org's events.

🤖 Generated with Claude Code