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/useClipboard.ts

@@ -0,0 +1,19 @@
+'use client'
+
+import { useCallback, useState } from 'react'
+
+/** Writes text to the clipboard and flags the copied key briefly (for a check-mark affordance). */
+export function useClipboard(resetMs = 1500) {
+  const [copiedKey, setCopiedKey] = useState<string | null>(null)
+
+  const copy = useCallback(
+    (key: string, text: string) => {
+      void navigator.clipboard?.writeText(text)
+      setCopiedKey(key)
+      window.setTimeout(() => setCopiedKey((k) => (k === key ? null : k)), resetMs)
+    },
+    [resetMs],
+  )
+
+  return { copiedKey, copy }
+}