ESPHome Device Builder: Renamed auth env vars silently disable dashboard authentication on upgrade
The dashboard reads its authentication credentials from $ESPHOME_USERNAME and $ESPHOME_PASSWORD. Earlier versions, and the legacy esphome dashboard, read the bare $USERNAME and $PASSWORD instead. When the env vars were renamed the bare names were dropped with no fallback, so an operator who had protected their dashboard with USERNAME / PASSWORD (as the older getting started guide documented) loses authentication on upgrade and the dashboard starts open to anyone who can …