Add "Allow globally" option to the tool approval prompt

Feature request

When Claude triggers a tool that requires approval, the prompt currently offers options like "Allow once" and "Allow for this session". It would be useful to also have an "Allow globally" option that adds the permission to the global settings (~/.claude/settings.json).

Since this is a more impactful action, it could require an additional confirmation step (e.g., "This will allow this tool globally across all projects. Confirm?") to prevent accidental global permissions.

Use case

When I find myself repeatedly approving the same tool across different projects and sessions, I end up manually editing settings.json to add the permission. Having this option directly in the approval prompt would save that step and make the workflow smoother.