[FEATURE] Introduce config flag for outputting with highlighting and markdown

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

I often need to copy the output of CC into GitHub or Slack. The underlying models seem to produce their output in markdown already, and the CC CLI is rendering the markdown nicely.
However, it would be nice to keep the colored rendering AND have the markdown characters, like ** or ` included in the output.
This makes the output easy to read on the CLI and easy to copy-paste.

Proposed Solution

Introduce a configuration flag.

Alternative Solutions

Allow putting a custom instruction for this into CLAUDE.md

Priority

High - Significant impact on productivity

Feature Category

Interactive mode (TUI)

Use Case Example

_No response_

Additional Context

_No response_