Expose subscription quota/reset info in statusLine JSON

Summary

The statusLine command feature pipes session-level JSON to scripts, but doesn't include any subscription-level usage data. For OAuth users on Pro/Max plans, it would be very useful to see weekly quota remaining and reset time in the status bar.

Requested Fields

Add to the statusLine JSON:

{
  "quota": {
    "used_percentage": 42,
    "reset_at": "2026-02-28T00:00:00Z",
    "plan": "max"
  }
}

Use Case

I built a custom statusline script showing model name + context usage. I'd like to also display how much of my weekly limit is left and when it resets, so I can pace my usage without switching to the web dashboard.

Current Workaround

Check https://claude.ai/settings/usage manually — no programmatic access from Claude Code.