Option to always show subscription usage gauge

Description

When approaching the Pro subscription usage limit, a gauge appears showing remaining usage. It would be helpful to have an option to display this gauge at all times, not just when near the limit.

Use case

As a Pro subscriber, I'd like to monitor my usage throughout the billing period to pace my usage effectively. Currently, I only learn about my consumption when I'm close to running out, which doesn't give much time to adjust.

Proposed solution

Add a configuration option (e.g., alwaysShowUsageGauge: true in settings) that displays the subscription usage indicator persistently in the status area.

Alternatives considered

Custom status line scripts can show per-session cost, but the subscription-level usage data isn't exposed to that API.