Expose rate limit usage (session %, weekly %) to statusLine configuration

Feature Request

Problem

The /usage command shows valuable rate limit information:

• Current session: X% used (5-hour billing window)
• Current week (all models): X% used (weekly limit)

However, this data is not available to the statusLine configuration. The statusLine only receives context window tokens and cost data, not the rate limit percentages.

Use Case

I want to see my session and weekly usage percentages persistently in the status bar without having to repeatedly open /usage. This would help me:

• Know when I'm approaching limits before hitting them
• Better pace my usage throughout the day/week
• Avoid interruptions from unexpected rate limit hits

Current Workaround

None that provides the exact same data. Tools like ccusage track 5-hour blocks from JSONL files but may not match the percentages shown in /usage.

Proposed Solution

Add rate limit data to the JSON structure passed to statusLine scripts:

{
  "rate_limits": {
    "session": {
      "used_percentage": 91,
      "resets_at": "2026-01-24T13:59:00-06:00"
    },
    "weekly": {
      "used_percentage": 81,
      "resets_at": "2026-01-29T08:59:00-06:00"
    }
  }
}

This would allow users to display rate limit info in their custom status lines.

Environment

• macOS Terminal
• Claude Code CLI