fix: clean up tab titles and sidebar session display

- Remove useless document.title from handleOpen (it only changed the
  caller page's title, not the new tab)
- Terminal tab title: simpler format without extra '— Headquarter' suffix
  - Single session: '{name} — Terminal'
  - Multiple sessions: '{name} · {session_name} — Terminal'
- Sidebar live sessions: show tool type in small muted text next to
  display_name so sessions aren't indistinguishable when display_name
  is just the workspace name

Quality gates: tsc --noEmit pass, npm run build pass, 82/82 tests pass

apps/web/src/hooks/use-instance-actions.ts

@@ -54,7 +54,6 @@ export function useInstanceActions(
 			url = `/projects/${session.project_id}`;
 		}
 
-		document.title = `${session.display_name} — Headquarter`;
 		const w = window.open(url, `session-${session.id}`);
 		tabRefs.current.set(key, w);
 	}, []);