Monthly spend limit notification should include the session/usage reset time

Describe the bug / feature gap

When a session is stopped because the monthly spend limit is reached, the notification tells you the session has been halted — but it does not say when the limit resets, i.e. when the session can be resumed through normal subscription usage.

Without the reset time, the user has no way to know (from the notification alone) whether they're blocked for an hour, until the next 5-hour session window, or until the next monthly billing cycle. They have to go dig through claude.ai settings or billing pages to find out.

Expected behavior

The spend-limit notification should include the reset timestamp, e.g.:

Monthly spend limit reached. Your session has been stopped. Usage resets at Aug 1, 12:00 AM UTC (or in your local timezone), at which point you can resume through your subscription.

Why it matters

• Users can plan around the reset instead of retrying blindly.
• Reduces confusion between the 5-hour session window reset, weekly limits, and the monthly spend limit reset — the notification currently gives no signal which one applies or how long the wait is.
• The information clearly exists server-side (usage windows are tracked), so surfacing it in the CLI message should be low-cost.

Environment

• Claude Code CLI on Linux
• Subscription plan with monthly spend limit / extra-usage cap enabled