Add syntax highlighting to Bash tool call labels

The Bash tool call label renders command text as plain monochrome. For longer commands, syntax highlighting would make it much easier to visually parse in conversations with many tool calls.

For example, this label is hard to scan as plain white text:

Bash(gh issue view 18728 --repo anthropics/claude-code --json state,title,comments --jq '{state: .state, title: .title, comment_count: (.comments | length)}')

The command output already renders ANSI colors correctly — this is specifically about the tool call header that Claude Code's UI generates.