Skip postprocessing for short composer input (#39744)

## What changed

Return the initial wrapping ranges directly when the composer input produces a
single line and its byte length is less than the available width. This avoids
the additional grapheme and word-boundary pass for input that cannot wrap.

GitOrigin-RevId: 55d990a354fcc61e9a90d5796b4b39d16742cc50

codex-rs/tui/src/bottom_pane/textarea/wrapping.rs

@@ -56,7 +56,7 @@ pub(super) fn wrapped_lines(text: &str, width: u16) -> Vec<Range<usize>> {
     let width = usize::from(width);
     let options = Options::new(width).wrap_algorithm(textwrap::WrapAlgorithm::FirstFit);
     let wrapped_lines = crate::wrapping::wrap_ranges(text, &options);
-    if width == 0 {
+    if width == 0 || (wrapped_lines.len() == 1 && text.len() < width) {
         return wrapped_lines;
     }