Add global setting to suppress verbose diff/edit output

Problem

When Claude Code makes edits, it displays large white-on-black code segments showing the changes. These scroll by quickly and are visually indistinguishable from user input, making it hard to find my own messages in the terminal history.

For users who trust Claude's edits (e.g., running in auto-accept mode), this output is noise rather than signal.

Request

A global setting (e.g., in ~/.claude/settings.json) to suppress or minimize the diff/change output shown after file edits. Something like:

{
  "preferences": {
    "diffOutput": "minimal"
  }
}

Options could be:

• "full" (current default — show entire changed blocks)
• "minimal" (show only filename and line count changed)
• "none" (suppress entirely)

This should apply globally across all sessions, not per-session.

Related Issues

• #9340
• #21246
• #14684