fix(support): agent-demo self-seeds (join default queue + go online); tickets always get a queue

Root cause of 'waiting for escalations': no queue/membership meant tickets were
never assigned. Now: createTicket find-or-creates a default queue; new joinDefault
endpoint + useGoOnline hook; agent-demo joins+goes-AVAILABLE on load (assignPending
picks up any waiting ticket). smoke-support self-seeds (no seed script needed).
Also: vitest singleFork to end cross-file DB races (45 tests deterministic).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/iios-support-web/src/index.ts

@@ -5,6 +5,7 @@ export {
   useAssignedTickets,
   useCallbackRequest,
   useAvailability,
+  useGoOnline,
 } from './react';
 // Re-export the chat hooks so a support app imports everything from one place.
 export { useThread, useMessages } from '@insignia/iios-message-web';