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.

browser_cli/models.py

@@ -44,6 +44,7 @@ class Tab:
   title: str = ""
   url: str = ""
   group_id: int | None = None
+  index: int = 0
   browser: str | None = None
   _browser: BoundBrowser | None = field(default=None, repr=False, compare=False, init=False)
 
@@ -149,6 +150,7 @@ class Group:
   color: str
   collapsed: bool
   tab_count: int
+  window_id: int | None = None
   browser: str | None = None
   _browser: BoundBrowser | None = field(default=None, repr=False, compare=False, init=False)