Add permission/execution mode to statusline JSON schema

Summary

The statusline input JSON doesn't expose the current permission/execution mode (plan mode, auto-accept, accept edits, ask always, etc.). This makes it impossible to display the active mode in custom statusline scripts.

Use Case

Users who customize their statusline via statusline-command.sh have no way to show which mode Claude Code is currently running in. This is useful context to have at a glance, especially when switching between plan mode and execution mode frequently.

Suggestion

Add a field like mode.name or permissions.level to the statusline JSON input, with values such as:

• plan
• auto-accept
• accept-edits
• ask-always

This would allow statusline scripts to render the current mode alongside model, context, and rate limit info.