fix(clifmt): fix operation order in diff background stripping
The previous fix stripped Chroma background colors, but it did so
AFTER replacing \\x1b[0m with diff bg+fg. This caused ansiBgRe to
also strip the diff background colors we had just inserted, leaving
gaps (black blocks) between syntax-highlighted tokens.
Fix the order: first strip all Chroma background colors, THEN replace
\\x1b[0m with our own diff background+foreground. This ensures the
diff's red/green background remains throughout the entire line.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
authored by