## What changed
- Add the disabled-by-default `tui_extensions_statusline` feature to render configured status items and their picker preview through a shared UI tree renderer.
- Support text, HTTP(S) links, rows, spacers, dividers, and gaps with rendering budgets, text sanitization, and width-aware truncation that keeps the ellipsis outside hyperlinks.
- Use plain text for the extension status line and hide the picker's theme color toggle while preserving the saved color preference.
## Testing
Add coverage for tree serialization and URL validation, Unicode widths, hyperlink clipping, picker previews, color preference preservation, and token usage updates across renderer switches.
GitOrigin-RevId: a6b87c2b1096765d61296d73e142834fcd53ceee
