What

• Fix the Ctrl+T transcript overlay so that very long exec output lines are soft‑wrapped to the viewport width instead of being rendered as a single truncated row.
• Add a regression test to TranscriptOverlay to ensure long exec outputs are rendered on multiple lines in the overlay.

Why

• Previously, the transcript overlay rendered extremely long single exec lines as one on‑screen row and simply cut them off at the right edge, with no horizontal scrolling.
• This made it impossible to inspect the full content of long tool/exec outputs in the transcript view, even though the main TUI view already wrapped those lines.
• Fixes Ctrl+T transcript overlay truncates very long single lines instead of wrapping to viewport width #7454.

How

• Update ExecCell::transcript_lines to wrap exec output lines using the existing RtOptions/word_wrap_line helpers so that transcript rendering is width‑aware.
• Reuse the existing line utilities to expand the wrapped Line values into the transcript overlay, preserving styling while respecting the current viewport width.
• Add transcript_overlay_wraps_long_exec_output_lines test in pager_overlay.rs that constructs a long single‑line exec output, renders the transcript overlay into a small buffer, and asserts that the long marker string spans multiple rendered lines.