feat(presence): dashboard Who's-here panel + /attendance + /me history + nav

Dashboard right column gets a 'Who's here' panel: present members with
Host badges + your own Check in / Check in as host / Check out with an
optional note (router.refresh after). New /attendance page (all members)
lists recent visits with status + duration + notes. /me gains a 'My
recent visits' section. Sidebar 'Attendance' link under People.

components/app-sidebar.tsx

@@ -15,7 +15,7 @@ import {
   MessageSquare, Users, CreditCard, BookUser, Download, LogOut,
   Vote, ShieldAlert, ScrollText, LineChart, UserCircle, UserSearch,
   MessagesSquare, SlidersHorizontal, ClipboardList, FileText, Award, BadgeCheck, GraduationCap, Hammer,
-  ChevronDown, DoorClosed,
+  ChevronDown, DoorClosed, CalendarCheck,
 } from 'lucide-react'
 
 interface NavLinkProps {
@@ -182,6 +182,7 @@ export function AppSidebar({ member, roleName, taskBadge = 0, commsBadge = 0, pa
 
         <NavSection id="people" title="People">
           <NavLink href="/members" label="Members" icon={Users} active={isActive('/members')} onClick={onNav} />
+          <NavLink href="/attendance" label="Attendance" icon={CalendarCheck} active={isActive('/attendance')} onClick={onNav} />
           <NavLink href="/contacts" label="Contacts" icon={BookUser} active={isActive('/contacts')} onClick={onNav} />
           {isAdmin && (
             <NavLink href="/recruitment" label="Recruitment" icon={UserSearch} active={isActive('/recruitment')} onClick={onNav} />