statusLine: allow custom status to render on same line as built-in permission indicator

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When using a custom statusLine command in settings.json, the output always renders on a separate line above the built-in permission mode indicator. This means the footer always takes two lines:

dirty 12 files | 72% ctx
⏵⏵ bypass permissions on (shift+tab to cycle)

Expected Behavior

It would be great if the custom statusLine content could be appended to the built-in permission indicator line, so the footer only takes one line:

⏵⏵ bypass permissions on (shift+tab to cycle) | dirty 12 files | 72% ctx

This would save vertical screen real estate. The second line is currently wasted when the custom statusLine output is short enough to fit alongside the built-in indicator.

Possible Approaches

• Allow the custom statusLine output to be appended/prepended to the built-in footer line
• Provide a config option to control whether the custom statusLine renders on its own line or inline with the built-in indicator
• Allow the built-in indicator line to be suppressed entirely when a custom statusLine is configured (so users can replicate the info themselves if they want)

Environment

• macOS (Darwin 25.3.0)
• Terminal: default macOS Terminal
• Claude Code: latest stable