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_rendering.py

@@ -0,0 +1,34 @@
+from os import terminal_size
+
+from rich.console import Console
+from rich.tree import Tree
+
+from browser_cli.commands import rendering
+
+def test_shorten_uses_ellipsis():
+  assert rendering.shorten("abcdef", 4) == "abc…"
+  assert rendering.shorten("abc", 4) == "abc"
+
+def test_terminal_width_prefers_shell_width_when_rich_is_redirected(monkeypatch):
+  monkeypatch.setattr(rendering.shutil, "get_terminal_size", lambda fallback: terminal_size((140, 20)))
+  assert rendering.terminal_width(Console(width=80)) == 140
+
+def test_tab_tree_label_is_reusable_no_wrap_text():
+  tab = type("Tab", (), {"id": 1, "title": "abcdef", "active": True, "url": "https://example.com"})()
+  label = rendering.tab_tree_label(tab, title_limit=4, show_urls=True, url_limit=12)
+  assert label.no_wrap is True
+  assert label.overflow == "ellipsis"
+  assert "abc…" in label.plain
+  assert "https://exa…" in label.plain
+
+def test_print_tree_uses_detected_width(monkeypatch):
+  widths = []
+  class CapturingConsole(Console):
+    def __init__(self, *args, **kwargs):
+      widths.append(kwargs.get("width"))
+      super().__init__(*args, **kwargs)
+
+  monkeypatch.setattr(rendering, "Console", CapturingConsole)
+  monkeypatch.setattr(rendering, "terminal_width", lambda console=None: 132)
+  rendering.print_tree(Tree("Root"))
+  assert widths == [132]