feat(admin): show paused sessions in live view; reset to live on logout

- Live cards freeze the worked timer at paused_at and show an amber
  "Gepauzeerd" badge plus a "Pauze H:MM:SS" total when paused.
- AuthContext.signOut resets the path to / so the next admin login lands
  on Live rather than the tab it logged out from.

apps/admin/src/screens/Live.test.tsx

@@ -23,6 +23,8 @@ function makeSession(over: Partial<WorkSession>): WorkSession {
     start_time: new Date(Date.now() - 65_000).toISOString(),
     end_time: null,
     duration_seconds: null,
+    paused_seconds: 0,
+    paused_at: null,
     status: 'active',
     source: 'app',
     notes: null,