Allow extension status content to use multiple footer rows (#60032)

## Why

Extension status content was limited to one row, clipping multiline text and content that wraps at narrow terminal widths.

## What changed

Measure extension status content at the available width and reserve up to four rows in both shared and separate status layouts. Account for mode indicators and warnings, and remeasure when content or available width changes.

Extra status rows yield to the draft and other composer surfaces when vertical space is limited. An unfocused composer keeps a single dim status row.

## Testing

Add regression coverage for resizing, wrapping beside mode indicators and warnings, hyperlink preservation, limited vertical space, cursor placement, footer overrides, focus changes, theme updates, and reasoning effort changes.

GitOrigin-RevId: 6a637b5cf6f34684639a92d920da4795c90abb6f

codex-rs/tui/src/ui_tree/render.rs

@@ -48,7 +48,6 @@ impl PreparedUiTree {
         })
     }
 
-    #[cfg_attr(not(test), expect(dead_code))] // Used by composer layout in the next change.
     pub(crate) fn measure(&self, bounds: Size) -> Size {
         layout(self.0.as_ref(), bounds, /*draw*/ None)
     }