[FEATURE] Expose rate limit / usage data in statusLine JSON input

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

Currently, the statusLine JSON input contains session info, context window tokens, and cost data, but it doesn't include the rate limit information shown by /usage.

Proposed Solution

Requested fields to add:

{
"usage_limits": {
"session": {
"used_percent": 5,
"resets_at": "2024-12-16T18:00:00+01:00"
},
"week": {
"used_percent": 14,
"resets_at": "2024-12-17T16:00:00+01:00"
},
"week_sonnet": {
"used_percent": 14,
"resets_at": "2024-12-17T16:00:00+01:00"
}
}
}

Alternative Solutions

_No response_

Priority

Low - Nice to have

Feature Category

CLI commands and flags

Use Case Example

This would allow users to display their current rate limit usage in the status line, helping them track usage without running /usage manually.

Additional Context

_No response_