Show local timezone (or allow configuring it) in /usage output

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

/usage currently reports reset times in UTC only, e.g.:
Current session: 96% used · resets Jul 26, 3:49pm (UTC)

Proposed Solution

It would be very helpful if this were displayed in the user's local timezone (auto-detected from the system), or at least offered as a configurable option (e.g. a timezone field in settings.json).
Why
Having to manually convert the UTC reset time to local time every time is a small but recurring friction point.
Suggested behavior
Detect and use the system's local timezone by default.
Optionally allow overriding via config (e.g. "timezone": "Europe/Berlin") for users who want a fixed zone.

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_