feat(advisor): topic threads, per-question delete/copy, fullscreen

Adds case management to the Compliance Advisor widget.

- topic threads: cases group into threads; the left menu shows each
  thread's first question as the Thema with expandable follow-ups.
  Send = follow-up to the active thread (carries the thread's prior Q&A
  as history for contextual answers); "+" starts a new topic.
- delete: a trash action per question (menu + stacked view).
- copy: single Q&A (question + answer + evidence + footnotes) or a whole
  thread, as Markdown to the clipboard (pure formatters in copy.ts).
- fullscreen: compact -> panel -> fullscreen view.
- route.ts consumes an optional bounded `history` so follow-ups are
  contextual for both the widget and the workspace consumer.

Tests: copy formatter unit tests + Playwright specs (threads/new-topic,
delete, fullscreen, copy affordance). No deploy.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

admin-compliance/components/sdk/advisor/CaseView.test.tsx

@@ -41,7 +41,7 @@ const answer: AdvisorResponse = {
 }
 
 function mk(response: AdvisorResponse): AdvisorCase {
-  return { id: 'case1', question: response.question, response, selectedContext: null, status: 'done' }
+  return { id: 'case1', threadId: 'thread1', question: response.question, response, selectedContext: null, status: 'done' }
 }
 
 describe('CaseView — clarify mode', () => {