[Feature Request] Add option to disable or customize diff syntax highlighting colors

Bug Description
The new addition deletion color highlighting is VERY off putting and straining my eyes. Please provide a way disable the new color highlighting or a way to modify the colors.

Environment Info

• Platform: darwin
• Terminal: iTerm.app
• Version: 2.0.71
• Feedback ID: 16290c16-e12c-480a-9270-89208238bc5a

Errors

[{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/krunal/.local/share/claude/versions/2.0.71 (expected in multi-process scenarios)\n    at hXR (/$bunfs/root/claude:2415:2165)\n    at JKA (/$bunfs/root/claude:2415:1885)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-12-17T20:08:12.235Z"}]