Right-anchored slide-in inbox triggered by the bell button. Backend is a
follow-up — for now this is a visual + behavior shell with mock fixtures,
same pattern as INCIDENT / FLAGS / OP_AUDIT.
- data/fixtures.ts: new NotificationItem type + 6 seed rows from the
design (DMARC, invitation, invoice, SAML, ticket reply, failed sign-in)
- useNotifications composable: isOpen + items + unreadCount + markRead +
markAllRead. Items deep-clone the fixture on first import so toggling
unread doesn't mutate the shared seed.
- NotificationDrawer component: Teleport + scrim + slide animation,
header/list/footer. Each row shows tone-tinted icon tile + title +
description + timestamp + left-rail unread dot. Click a row to mark
read; click Mark all read or Preferences in the footer.
- OpTopbar: bell now opens the drawer and only shows .icon-btn-dot when
unreadCount > 0.
- Layout mounts <NotificationDrawer /> alongside the other floating
components.
Dismissal: backdrop click, Escape, X, and route-change watcher (so
Preferences → /settings closes the drawer cleanly).