Scenario s40 (toolbar customisation survives a restart) runs now

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL

crates/ui-egui/tests/scenarios/s40_toolbar_customize_persists.json

@@ -1,7 +1,4 @@
 [
- {
-  "pending": "toolbar Pin/Remove/reorder (toolbar:<id> handles, ui.menu toolbar_command) and a full-height workspace switcher (solvecraft-shell)"
- },
  {
   "note": "Toolbar customizing like Fusion survives a restart: Pin to Toolbar, Remove from Toolbar, drag to reorder. Toolbar buttons publish handles `toolbar:<command id>`. The workspace switcher spans the toolbar's height."
  },