Render ASCII control characters (0x00-0x1F, 0x7F) as Unicode Control
Pictures (U+2400-U+2421) instead of text abbreviations like [DEL] or
[U+001E]. This applies to both the file view and diff view paths.
Also style control char badges in red without background, matching
the style of other escaped code points.
Co-Authored-By: Claude (Opus 4.6) <noreply@anthropic.com>