fix(login): reuse a valid session instead of always starting a device flow (#651) - #658

Bugbot Analysis Progress (3m 38s elapsed)

✅ Gathered PR context (2s)
✅ Completed bug detection (3m 35s)
✅ Posted analysis results (1s)

Final Result: Bugbot completed review - no issues found! ✅

Request ID: serverGenReqId_f5514fa2-c9d4-4e54-b2c0-9dee67a7af24