[Feature Request] Respect terminal color palette in diff output instead of hardcoded truecolor codes

Bug Description
Claude Code diffs use hardcoded truecolor (24-bit) RGB escape codes instead of
ANSI color references. This means terminal color palettes are completely
bypassed — users who customize their terminal theme for accessibility (e.g.
post-LASIK eye sensitivity, low contrast needs) get no benefit in Claude Code's
diff output even though the rest of their terminal looks correct.

Request: Either add a color/theme config for Claude Code's UI, or provide an
option to use standard ANSI color codes so terminal themes are respected.

Environment Info

• Platform: linux
• Terminal: kitty
• Version: 2.1.96
• Feedback ID: acbadae7-39ed-447b-bc8e-f030febf1299

Errors

[{"error":"Error: Claude Code web sessions require authentication with a Claude.ai account. API key authentication is not sufficient. Please run /login to authenticate, or check your authentication status with /status.\n    at bD (/$bunfs/root/src/entrypoints/cli.js:1961:9482)\n    at xb9 (/$bunfs/root/src/entrypoints/cli.js:1961:13902)\n    at tlK (/$bunfs/root/src/entrypoints/cli.js:1961:14538)\n    at dK1 (/$bunfs/root/src/entrypoints/cli.js:5187:13345)\n    at FK1 (/$bunfs/root/src/entrypoints/cli.js:5187:13422)\n    at K3 (/$bunfs/root/src/entrypoints/cli.js:479:26047)\n    at useState (/$bunfs/root/src/entrypoints/cli.js:479:104855)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:470:8183)\n    at ai$ (/$bunfs/root/src/entrypoints/cli.js:5187:13382)\n    at eZ7 (/$bunfs/root/src/entrypoints/cli.js:5979:22422)\n    at async <anonymous> (/$bunfs/root/src/entrypoints/cli.js:16830:1324)","timestamp":"2026-04-08T07:27:11.673Z"},{"error":"MaxFileReadTokenExceededError: File content (17578 tokens) exceeds maximum allowed tokens (10000). Use offset and limit parameters to read specific portions of the file, or search for specific content instead of reading the whole file.\n    at Zz7 (/$bunfs/root/src/entrypoints/cli.js:4307:13191)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-08T07:31:00.757Z"}]