Add streaks, today view, custom plan editing/chapter ranges, and ntfy reminders

Reading plans now track a cross-plan activity log for streaks, surface a
combined "today's reading" view on both Home and the Reading Plans page,
and let custom plans be edited after creation (including narrowing a book
to a specific chapter range). The reader auto-marks a plan's day read after
a dwell period, active plans that fall behind their pace get a "catch me
up" banner, and a new Settings section wires up daily reading reminders
via ntfy.sh, checked once a minute by a small server-side scheduler.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/syncService.js

@@ -159,6 +159,11 @@ export async function changePassword(currentPassword, newPassword) {
   return request('POST', '/auth/change-password', { currentPassword, newPassword });
 }
 
+/** Sets the daily reading reminder sent via ntfy.sh ({ reminderEnabled, ntfyUrl, ntfyTopic, reminderTime }). */
+export async function updateReminderSettings(settings) {
+  return request('PATCH', '/auth/reminder-settings', settings);
+}
+
 // ---------------------------------------------------------------------------
 // Two-factor auth setup (Account Settings page)
 // ---------------------------------------------------------------------------