Render Markdown links as clickable labels in supported terminals (#40471)

## What changed

- Render web-link labels in cyan with an underline and hide the repeated destination in recognized terminals with hyperlink support.
- Keep destinations visible for unknown terminals, multiplexers, non-terminal output, and empty labels so the URL remains usable.
- Preserve OSC 8 link targets through prose and table wrapping, streaming updates, transcript clipping, and pager scrolling.

## Testing

- Add coverage for terminal detection, label formatting and fallbacks, wrapped tables and prose, streaming parity, history output, and scrolled transcript rendering.

GitOrigin-RevId: 4a09e41e349ba299022a9c00f0c25892d9aaefe3

codex-rs/tui/src/streaming/snapshots/codex_tui__streaming__render__tests__incremental_render_representative_stream.snap

@@ -17,7 +17,7 @@ expression: render.lines
     HyperlinkLine {
         line: Line::from_iter([
             Span::from("First paragraph with a "),
-            Span::from("link"),
+            Span::from("link").cyan().underlined(),
         ]),
         hyperlinks: [
             TerminalHyperlink {