Users who have linked their Discord account can enable a ping preference
in Settings > Notifications. When enabled, their bracket username is replaced
with a Discord @mention (<@userId>) in league standings update messages,
sending them a push notification and showing their Discord display name.
Adds discordPingEnabled column to users, a findDiscordIdsByUserIds model
helper, allowed_mentions support to the Discord webhook payload, and a
NotificationsSection settings component.
https://claude.ai/code/session_01NUv93WRrufHhpZSMyY4bjs
