Family devices: shared-screen family board with a who-is-this profile picker

- Admin can make a screen a family device; it opens on a family board
- Name tiles with KID labels; kids tap, others enter a PIN (lockout after 5 wrong tries)
- Name label with Switch user, auto-return to the board after 5 idle minutes
- Short 30-minute sessions on family devices
- Settings section for PIN and turning a device on or off
- Test, README and roadmap updated

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

chat.js

@@ -239,4 +239,4 @@ function searchFor(me, q) {
   for (const c of convs().filter(x => x.members.includes(me.id))) { const cv = view(c, me.id, st); for (const x of msgs(c.id)) if (!x.deleted && !x.sys && x.text && x.text.toLowerCase().includes(needle)) out.push({ conv: c.id, convName: cv.name, msg: msgView(x, me.id) }); }
   return out.sort((a, b) => b.msg.ts - a.msg.ts).slice(0, 8);
 }
-module.exports = { handle, totalUnread, purge, parsePreview, askParents, searchFor };
+module.exports = { announcement: () => read(annFile(), null), handle, totalUnread, purge, parsePreview, askParents, searchFor };