[Bug] OAuth token expiration causing repeated 401 authentication errors during active sessions

Question

**Bug Description**
starting today, i keep getting a 401 error during my claude code sessions. i've been using claude code for months and only started getting this error today. I shouldn't need to re-run the /login command multiple times per day. i've gotten it 3 times in a <5 hour window. Error:

```
API Error: 401 {"type":"error","error":{"type":"authentication_error","message":"OAuth token has expired. Please obtain a new token or refresh your existing token."},"request_id":"req_011CX7zT7Swc3