[BUG] /usage heatmap is off by one weekday

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The month X weekday heatmap doesn't map weekdays correctly. It shows usage shifted by one weekday. What should be Monday is shown instead for Tuesday etc.

It is probably not simply time zone related as I'm UTC+2, so if anything it should be shifted in the other direction.

What Should Happen?

Move the heatmap one day up or fix the legend.

Error Messages/Logs

Steps to Reproduce

/usage

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.150

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_