feat(cli): improve tab and window tree rendering

- Add shared rendering helpers for width-aware tree labels, truncation, and no-wrap Rich text.
- Preserve tab index and group window metadata through the extension and SDK factories.
- Render tab trees in browser/window/index order with grouped tab details and optional shortened URLs.
- Reuse the tab tree labels in window trees to keep output compact and consistent.
- Cover legacy missing-index responses, grouped/collapsed tabs, URL display, and rendering helpers with tests.

tests/test_api.py

@@ -18,6 +18,7 @@ TAB_DATA = {
   "id": 10,
   "windowId": 1,
   "active": True,
+  "index": 3,
   "title": "Example",
   "url": "https://example.com",
   "groupId": None,
@@ -73,6 +74,15 @@ class TestBrowserCLIInit:
     assert b.remote == "browser-host.example:443"
     assert b.key == "agent"
 
+  def test_tab_factory_preserves_index(self):
+    tab = BrowserCLI().tab_from(TAB_DATA)
+    assert tab.index == 3
+
+  def test_tab_factory_defaults_missing_index_to_zero(self):
+    data = {key: value for key, value in TAB_DATA.items() if key != "index"}
+    tab = BrowserCLI().tab_from(data)
+    assert tab.index == 0
+
   def test_namespaces_present_and_bound(self):
     b = BrowserCLI()
     for name in ("nav", "tabs", "groups", "windows", "dom", "extract",