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/styles/utilities.css

@@ -298,6 +298,14 @@ a.nav-item,
 	max-width: 140px;
 }
 
+.session-tool {
+	font-size: 10px;
+	color: var(--muted);
+	margin-left: 4px;
+	text-transform: uppercase;
+	letter-spacing: 0.03em;
+}
+
 .nav-divider {
 	height: 1px;
 	background: var(--border);